CN1549633A - TD-SCDMA/GSM UE dual-mode multi-band transceiver intermediate frequency selection method - Google Patents

Abstract

Translated fromChinese

一种TD－SCDMA/GSM UE双模多频段收发信机的中频频率选择方法，其方法是依据避免接收机内各种信号谐波及其组合干扰的限制条件，通过编程分别计算出TD－SCDMA/GSM UE双模多频段收发信机的各接收频段的中频频率可选取范围，并在此基础上找出这样的TD－SCDMA UE和GSM UE的接收和发中频频率该方法对于避免接收机各种可能的组合干扰，提高收信机抗干扰能力并对频率合成电路的优化设计、降低其成本都是一种十分有效的方法。

A TD-SCDMA/GSM UE dual-mode multi-band transceiver IF frequency selection method, the method is based on the constraints of avoiding various signal harmonics and their combined interference in the receiver, respectively calculate the TD-SCDMA frequency through programming /GSM UE dual-mode multi-band transceivers can select the range of IF frequencies for each receiving frequency band, and on this basis, find out the receiving and sending IF frequencies of such TD-SCDMA UE and GSM UE. It is a very effective method to improve the anti-interference ability of the receiver and optimize the design of the frequency synthesis circuit and reduce its cost.

Description

Translated fromChinese

TD-SCDMA/GSM UE双模多频段收发信机中频选择方法TD-SCDMA/GSM UE dual-mode multi-band transceiver intermediate frequency selection method

一.技术领域1. Technical field

本发明涉及一种TD-SCDMA/GSM UE双模多频段收发信机频率合成装置中频选择方法，属于移动通信系统技术领域，具体涉及第三代移动通信系统。The invention relates to an intermediate frequency selection method for a TD-SCDMA/GSM UE dual-mode multi-band transceiver frequency synthesis device, belongs to the technical field of mobile communication systems, and specifically relates to third-generation mobile communication systems.

二.背景技术2. Background technology

在TD-SCDMA/GSM UE双模多频段收发信机频率合成装置中，由于要实现TD-SCDMAUE和GSM UE相互兼容，完成第二代GSM通信网向第三代TD-SCDMA通信网的平滑过渡，需要考虑的各种干扰相对较多。根据信息产业部“信部无[2002]479号文”关于第三代公众移动通信系统频率划分的规定，分配给TD-SCDMA第三代公众移动通信系统155MHz非对称的时分双工(TDD)可运营频段。这155MHz带宽是分布在1880-1920MHz，2010-2025MHz和2300-2400MHz共三个频段。而GSM UE的接收和发射频段是分别为935-960MHz，890-915MHz。显然，TD-SCDMA/GSM UE射频前端电路要实现TD-SCDMA UE和GSM UE相互兼容，即是要在完成上述TD-SCDMA UE在1880-1920MHz，2010-2025MHz和2300-2400MHz接收或发射的同时，还应能完成GSM UE在935-960MHz频段的接收和890-915MHz频段的发射。为此，TD-SCDMA/GSM UE接收或发送所需的本振信号必须有相应的射频和中频锁相环及其VCO来支持，而其VCO的频率覆盖范围和接收机的各种组合干扰频率点的分布都是因收发信机的中频选择不同而异。为避免TD-SCDMA/GSMUE内各种信号的谐波及其交调信号对接收机的干扰，并优化TD-SCDMA/GSM双模多频收发信机的射频和中频锁相环及其相应VCO的电路设计，TD-SCDMA/GSM UE双模收发机中频频率的选择成为关键。In the TD-SCDMA/GSM UE dual-mode multi-band transceiver frequency synthesis device, due to the mutual compatibility between TD-SCDMA UE and GSM UE, complete the smooth transition from the second generation GSM communication network to the third generation TD-SCDMA communication network , there are relatively many kinds of interference that need to be considered. According to the Ministry of Information Industry's "Xinbu Wu [2002] No. 479 Document" on the frequency division of the third-generation public mobile communication system, the 155MHz asymmetrical time-division duplex (TDD) allocated to the TD-SCDMA third-generation public mobile communication system available frequency bands. The 155MHz bandwidth is distributed in three frequency bands: 1880-1920MHz, 2010-2025MHz and 2300-2400MHz. The receiving and transmitting frequency bands of GSM UE are 935-960MHz and 890-915MHz respectively. Obviously, the TD-SCDMA/GSM UE radio frequency front-end circuit needs to realize mutual compatibility between TD-SCDMA UE and GSM UE, that is, to complete the above-mentioned TD-SCDMA UE receiving or transmitting at 1880-1920MHz, 2010-2025MHz and 2300-2400MHz , It should also be able to complete the reception of GSM UE in the 935-960MHz frequency band and the transmission of the 890-915MHz frequency band. For this reason, the local oscillator signal required by TD-SCDMA/GSM UE reception or transmission must be supported by the corresponding radio frequency and intermediate frequency phase-locked loop and its VCO, and the frequency coverage of the VCO and various combinations of the receiver interfere with the frequency The distribution of points is different due to the selection of the intermediate frequency of the transceiver. In order to avoid the interference of the harmonics and intermodulation signals of various signals in TD-SCDMA/GSMUE to the receiver, and optimize the RF and IF phase-locked loops and corresponding VCOs of TD-SCDMA/GSM dual-mode multi-frequency transceivers The circuit design of TD-SCDMA/GSM UE dual-mode transceiver IF frequency selection becomes the key.

三.发明内容3. Contents of the invention

本发明的目的是依据避免接收机内各种信号谐波及其组合干扰的限制条件，分别计算出TD-SCDMA/GSM UE双模多频段收发信机的各接收频段的中频频率可选取范围，并在此基础上找出TD-SCDMA UE和GSM UE的接收和发射中频频率。选择接收机中频的限制条件为：The purpose of the present invention is to calculate respectively the selectable range of the intermediate frequency frequency of each receiving frequency band of the TD-SCDMA/GSM UE dual-mode multi-band transceiver according to the restriction conditions of avoiding various signal harmonics and combined interference in the receiver, And on this basis, find out the receiving and transmitting intermediate frequency of TD-SCDMA UE and GSM UE. The constraints for selecting the receiver IF are:

1，为更好地抑制接收信号的镜频干扰，接收机应选择高中频f_IF，其所选接收机中频f_IF-RX应满足条件：150MHz≤f_IF-RX≤350MHz1. In order to better suppress the image frequency interference of the received signal, the receiver should select the high-frequency f_IF , and the selected receiver intermediate frequency f_IF-RX should meet the conditions: 150MHz≤f_IF-RX ≤350MHz

2，选择接收中频f_IF-RX应大于接收信号带宽B_i的3/2倍以满足其无三阶互调的要求，即$f_{\mathrm{IF}-\mathrm{RX}}>\frac{3}{2}{B}_i.$其中，B_i为接收射频信号带宽。2. The selected receiving intermediate frequency f_IF-RX should be greater than 3/2 times of the received signal bandwidth_Bi to meet its requirement of no third-order intermodulation, namely$f_{\mathrm{IF}-\mathrm{RX}}>\frac{3}{2}{B}_i.$ Among them, B_i is the bandwidth of the received radio frequency signal.

3，接收机中频f_IF-RX的任意次谐波n×f_IF-RX不应落在接收射频带内，以避免对收信机的固定干扰。即$n\×f_{\mathrm{IF}-\mathrm{RX}}\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{Band}}.$其中，f_RF-RX-Band为接收射频频带；n为任意的正整数。3. Any harmonic n×f_IF-RX of the receiver intermediate frequency f_IF-RX should not fall within the receiving radio frequency band to avoid fixed interference to the receiver. Right now$\mathrm{no}\×f_{\mathrm{IF}-\mathrm{RX}}\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{band}}.$ Wherein, f_RF-RX-Band is the receiving radio frequency band; n is any positive integer.

4，参考时钟频率f_R的任意次谐波n×f_R不应落在接收机的射频和中频带内，即$n\×f_R\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{Band}};$$n\×f_R\∉f_{\mathrm{IF}-\mathrm{RX}-\mathrm{Band}}.$其中，f_RF-RX-Band为接收射频频带；f_IF-RX-Band为接收机的中频频带；n为任意的正整数。4. Any harmonic n×f_R of the reference clock frequency f_R should not fall within the RF and IF bands of the receiver, ie$\mathrm{no}\×f_R\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{band}};$$\mathrm{no}\×f_R\∉f_{\mathrm{IF}-\mathrm{RX}-\mathrm{band}}.$ Wherein, f_RF-RX-Band is the receiving radio frequency band; f_IF-RX-Band is the intermediate frequency band of the receiver; n is any positive integer.

5，同样，DSP工作时钟速率f_S的任意次谐波n×f_S不应落在接收射频和中频带内，即$n\×f_S\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{Band}};$$n\×f_S\∉f_{\mathrm{IF}-\mathrm{RX}-\mathrm{Band}}.$其中，f_RF-RX-Band为射频接收频带；f_IF-RX-Band为接收中频频带；n为任意的正整数。5. Similarly, any harmonic n×f_S of the DSP operating clock rate f_S should not fall within the receiving radio frequency and intermediate frequency bands, that is,$\mathrm{no}\×f_S\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{band}};$$\mathrm{no}\×f_S\∉f_{\mathrm{IF}-\mathrm{RX}-\mathrm{band}}.$ Wherein, f_RF-RX-Band is the radio frequency receiving frequency band; f_IF-RX-Band is the receiving intermediate frequency frequency band; n is any positive integer.

6，基带ADC的取样时钟速率f_B的任意次谐波n×f_B不应落在接收射频和中频带内，即$n\×f_B\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{Band}};$$n\×f_B\∉f_{\mathrm{IF}-\mathrm{RX}-\mathrm{Band}}.$其中，_fRF-RX-Band为射频接收频带；f_IF-RX-Band为接收中频频带；n为任意的正整数。6. Any harmonic n×f_B of the sampling clock rate f_B of the baseband ADC should not fall within the receiving radio frequency and intermediate frequency bands, that is$\mathrm{no}\×f_B\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{band}};$$\mathrm{no}\×f_B\∉f_{\mathrm{IF}-\mathrm{RX}-\mathrm{band}}.$ Wherein,_fRF-RX-Band is a radio frequency receiving frequency band; f_IF-RX-Band is a receiving intermediate frequency frequency band; n is any positive integer.

根据上述TD-SCDMA/GSM UE接收中频选择的限制条件，确定TD-SCDMA UE和GSM UE收信机中频频率的方法及步骤如下：According to the restriction conditions of TD-SCDMA/GSM UE receiving IF selection mentioned above, the method and steps of determining the IF frequency of TD-SCDMA UE and GSM UE receiver are as follows:

1).当TD-SCDMA UE接收机在1880-1920MHz频段工作时，若接收机采用外差方案，则射频VCO的频率范围应为[(1880-1920)+f_IF-TSM-A]MHz。根据上述TD-SCDMA/GSMUE接收中频选择的限制条件(1)-(6)，通过编程计算得出此时接收中频f_IF-TSM-A的可选取范围。1). When the TD-SCDMA UE receiver works in the 1880-1920MHz frequency band, if the receiver adopts the heterodyne scheme, the frequency range of the RF VCO should be [(1880-1920)+f_IF-TSM-A ]MHz. According to the restriction conditions (1)-(6) of the above-mentioned TD-SCDMA/GSMUE receiving IF selection, the selectable range of receiving IF f_IF-TSM-A at this time is obtained through programming calculation.

2).当TD-SCDMA UE接收机在2010-2025MHz频段工作时，若接收机采用外差方案，则射频VCO的频率范围应为[(2010-2025)+_fIF-TSM-B]MHz。根据上述TD-SCDMA/GSMUE接收中频选择的限制条件(1)-(6)，通过编程计算得出此时接收中频f_IF-TSM-B的可选取范围。2). When the TD-SCDMA UE receiver works in the 2010-2025MHz frequency band, if the receiver adopts the heterodyne scheme, the frequency range of the RF VCO should be [(2010-2025)+_fIF-TSM-B ]MHz. According to the restriction conditions (1)-(6) for TD-SCDMA/GSMUE receiving IF selection mentioned above, the selectable range of receiving IF f_IF-TSM-B at this time is obtained through programming calculation.

3).当TD-SCDMA UE接收机在2300-2400MHz频段工作时，若接收机采用内差方案，则射频VCO的频率范围应为[(2300-2400)-f_IF-TSM-C]MHz。根据上述TD-SCDMA/GSMUE接收中频选择的限制条件(1)-(6)，通过编程计算得出此时接收中频f_IF-TSM-C的可选取范围。3). When the TD-SCDMA UE receiver works in the 2300-2400MHz frequency band, if the receiver adopts the interdyne scheme, the frequency range of the radio frequency VCO should be [(2300-2400)-f_IF-TSM-C ]MHz. According to the restriction conditions (1)-(6) of the above-mentioned TD-SCDMA/GSMUE receiving IF selection, the selectable range of receiving IF f_IF-TSM-C at this time is obtained through programming calculation.

4).从上述第1)、2)、3)步骤所计算出的f_IF-TSM-A，f_IF-TSM-B，f_IF-TSM-C中，求出它们所共有的中频频率点f_IF-TSM-RX。这正是TD-SCDMA UE接收机中频的可选取范围。4). From the f_IF-TSM-A , f_IF-TSM-B , and f_IF-TSM-C calculated in the above steps 1), 2), and 3), find the intermediate frequency points shared by them f_IF-TSM-RX . This is the selectable range of the intermediate frequency of the TD-SCDMA UE receiver.

5).因TD-SCDMA UE的接收和发射频率相同，所以应选取TD-SCDMA UE的发射中频f_{IF-TSM_TX}应与TD-SCDMA UE的接收中频f_IF-TSM-RX相同，即f_{IF-TSM_TM}＝f_IF-TSM-RX＝f_IF-TSM。这样只要TD-SCDMA UE在1880-1920MHz和2010-2025MH频段工作采用变频下边带发射；而2300-2400MHz则采用变频上边带发射。算出TD-SCDMA UE发射机所需的射频VCO的频率覆盖范围f_{RF-TSM-VCO-TX}与TD-SCDMAUE收信机所需的射频VCO的频率范围f_{RF-TSM-VCO-RX}是完全一样的。即TD-SCDMA UE收发完全共用一个射频本振频率，这样在收发时隙转换时，射频本振的频率则不需转换。5). Since the receiving and transmitting frequencies of TD-SCDMA UE are the same, the transmitting intermediate frequency f_{IF-TSM_TX} of TD-SCDMA UE should be selected to be the same as the receiving intermediate frequency f_IF-TSM-RX of TD-SCDMA UE, that is, f_{IF- TSM_TM} = f_{IF - TSM - RX} = f_{IF - TSM} . In this way, as long as the TD-SCDMA UE works in the 1880-1920MHz and 2010-2025MH frequency bands, it adopts frequency conversion lower sideband transmission; while 2300-2400MHz adopts frequency conversion upper sideband transmission. Calculate the frequency coverage f_{RF-TSM-VCO-TX} of the RF VCO required by the TD-SCDMA UE transmitter and the frequency range f_{RF-TSM-VCO-RX} of the RF VCO required by the TD-SCDMA UE receiver is exactly the same of. That is to say, TD-SCDMA UEs transmit and receive completely share one radio frequency local oscillator frequency, so when the time slots for transmitting and receiving are switched, the frequency of the radio frequency local oscillator does not need to be switched.

6).当GSM UE接收机在935-960MHz频段工作时，若接收机采用外差方案并将射频VCO的本振信号在参与接收下变频前经除2电路分频，则射频本振的频率范围应为2×[(935-960)+f_IF-GSM-RX]MHz。根据上述TD-SCDMA/GSM UE接收中频选择的限制条件(1)-(6)，通过编程计算，则可得出此时接收中频f_IF-GSM-RX的可选取范围。这正是GSM UE接收机的中频可选取范围。6). When the GSM UE receiver works in the 935-960MHz frequency band, if the receiver adopts the heterodyne scheme and the local oscillator signal of the RF VCO is divided by 2 before participating in the receiving down-conversion, the frequency of the RF local oscillator The range should be 2×[(935-960)+f_IF-GSM-RX ]MHz. According to the restriction conditions (1)-(6) for TD-SCDMA/GSM UE receiving IF selection above, the selectable range of receiving IF f_IF-GSM-RX can be obtained through programming calculation. This is the selectable range of IF for GSM UE receivers.

7).若选取GSM UE的发射中频f_{IF-GSM_TX}较GSM UE的接收中频f_IF-GSM-RX高45MHz，即f_{IF-GSM_TX}＝(f_IF-GSM-RX+45)MHz。若这时发射时采用变频下边带发射，并对射频VCO的发本振信号在参与发信变频前需经除2电路分频，则不难算出GSM UE发射机所需的射频VCO的频率范围f_{RF-GSM-VCO-TX}＝2×[(890-915)+f_{IF-GSM_TX}]MHz＝2×[(935-960)+f_IF-GSM-RX]。这与GSM UE收信机所需的射频本振的频率范围完全相同。则GSM UE接收和发射的射频本振同样实现了共用。7). If the transmit intermediate frequency f_{IF-GSM_TX} of the GSM UE is selected to be 45 MHz higher than the receive intermediate frequency f_IF-GSM-RX of the GSM UE, that is, f_{IF-GSM_TX} = (f_IF-GSM-RX +45) MHz. If the frequency conversion lower sideband transmission is used for transmission at this time, and the local oscillator signal of the RF VCO needs to be divided by 2 before participating in the frequency conversion of the signal, then it is not difficult to calculate the frequency range of the RF VCO required by the GSM UE transmitter f_{RF-GSM-VCO-TX} = 2×[(890-915)+f_IF-GSM-TX ] MHz=2×[(935-960)+f_IF-GSM-RX ]. This is exactly the same frequency range as the RF LO required for GSM UE receivers. Then the radio frequency local oscillators of the GSM UE receiving and transmitting are also shared.

8).不论是TD-SCDMA UE或是GSM UE，因在进行正交调制或正交解调时，其所需中频本振信号都需经除2电路分频，所以若选择TD-SCDMA UE的收发中频为f_IF-TSM；GSM UE的收发中频为f_IF-GSM。则TD-SCDMA/GSM UE所需的中频本振频率的覆盖范围则为f_IF-VCO＝2×(f_IF-TSM_f_IF-GSM)8). Regardless of whether it is TD-SCDMA UE or GSM UE, when performing quadrature modulation or quadrature demodulation, the required IF local oscillator signal needs to be divided by 2 circuits, so if you choose TD-SCDMA UE The transmitting and receiving intermediate frequency of the GSM UE is f_IF-TSM ; the transmitting and receiving intermediate frequency of the GSM UE is f_IF-GSM . Then the TD-SCDMA/GSM UE needs the coverage of the IF local oscillator frequency as f_IF-VCO =2×(f_IF-TSM _f_IF-GSM )

9).若选取TD-SCDMA的接收中频f_IF-TSM-Rx为186MHz，则可算出为同时满足TD-SCDMA UE在1980-1920MHz；2010-2025MHz；2300-2400MHz接收和发射的需要，其射频VCO的频率范围应为2066-2214MHz。9). If the receiving intermediate frequency f_IF-TSM-Rx of TD-SCDMA is selected as 186MHz, it can be calculated to meet the needs of TD-SCDMA UE receiving and transmitting at 1980-1920MHz; The frequency range of the VCO should be 2066-2214MHz.

10).若选取GSM的接收中频为163MHz，则可算出为同时满足GSM在890-915MHz频段发射和935-960MHz频段接收的需要，其射频VCO的频率范围应为2196-2246MHz。10). If the receiving intermediate frequency of GSM is 163MHz, it can be calculated that the frequency range of the radio frequency VCO should be 2196-2246MHz in order to meet the needs of GSM transmitting in the 890-915MHz frequency band and receiving in the 935-960MHz frequency band at the same time.

本发明是依据避免接收机内各种信号谐波及其组合干扰的限制条件，通过编程分别计算出TD-SCDMA/GSM UE双模多频段收发信机的各接收频段的中频频率可选取范围。并在此基础上找出这样的TD-SCDMA UE和GSM UE的接收和发中频频率，即能减少TD-SCDMA/GSM UE双模射频前端的射频VCO和中频VCO的覆盖范围，最终实现TD-SCDMA/GSM UE双模多频段收发信机共享一个射频VCO和中频VCO之目的。该方法对于避免接收机各种可能的组合干扰，提高收信机抗干扰能力并对频率合成电路的优化设计、降低其成本都是一种十分有效的方法。The present invention calculates the selectable range of the intermediate frequency of each receiving frequency band of the TD-SCDMA/GSM UE dual-mode multi-band transceiver through programming based on the restriction conditions of avoiding various signal harmonics and combined interference in the receiver. And on this basis, find out such TD-SCDMA UE and GSM UE receiving and transmitting IF frequencies, which can reduce the coverage of the RF VCO and IF VCO of the TD-SCDMA/GSM UE dual-mode RF front end, and finally realize the TD-SCDMA/GSM UE. SCDMA/GSM UE dual-mode multi-band transceivers share the purpose of a radio frequency VCO and intermediate frequency VCO. This method is a very effective method for avoiding various possible combined interference of the receiver, improving the anti-interference ability of the receiver, optimizing the design of the frequency synthesis circuit, and reducing its cost.

下面结合附图对本发明做进一步的说明。The present invention will be further described below in conjunction with the accompanying drawings.

四.附图说明4. Description of drawings

图1为TD-SCDMA/GSM UE RX中频选择计算流程；Figure 1 is the TD-SCDMA/GSM UE RX intermediate frequency selection calculation process;

图2为TD-SCDMA UE RX f_IF-TSM-A计算流程；Figure 2 is the TD-SCDMA UE RX f_IF-TSM-A calculation process;

图3为TD-SCDMA UE RX f_IF-TSM-B计算流程；Figure 3 is the TD-SCDMA UE RX f_IF-TSM-B calculation process;

图4为TD-SCDMA UE RX f_IF-TSM-C计算流程；Figure 4 is the TD-SCDMA UE RX f_IF-TSM-C calculation process;

图5为GSM UE RX f_IF-GSM-RX计算流程。Fig. 5 is a calculation flow of GSM UE RX f_IF-GSM-RX .

五.具体实施方式5. Specific implementation

中频选择限制条件的确定Determination of Restrictive Conditions for IF Selection

当TD-SCDMA/GSM UE双模多频段收发信机工作时，在机内必然同时存在着有相应的参考时钟f_R，DSP工作时钟f_S，ADC采样频率f_B，中频本振f_LL，射频本振f_RL和接收机的中频信号f_IF及其它们所对应的各种谐波信号。所以，在选择TD-SCDMA UE和GSMUE的接收机中频时，首先必须避免接收机内各种信号的谐波及其组合干扰信号落在接收射频信号或接收中频信号带内使之成为对接收机的固有干扰。同时，因接收和发射的射频本振频率范围与所选接收和发射的中频直接相关，所以，在选择TD-SCDMA UE和GSM UE的接收机和发射机的中频时还应尽力减少射频VCO和中频VCO的覆盖范围，从而减少射频VCO和中频VCO的数量，以实现优化其所需的频率合成电路的设计之目的。为此，首先给出下列选择接收机中频的限制条件。When the TD-SCDMA/GSM UE dual-mode multi-band transceiver is working, there must be corresponding reference clock f_R , DSP working clock f_S , ADC sampling frequency f_B , intermediate frequency local oscillator f_LL , The radio frequency local oscillator f_RL and the receiver's intermediate frequency signal f_IF and their corresponding harmonic signals. Therefore, when selecting the receiver intermediate frequency of TD-SCDMA UE and GSMUE, first of all, it is necessary to avoid the harmonics of various signals in the receiver and their combined interference signals falling within the band of receiving radio frequency signals or receiving intermediate frequency signals to make it a problem for the receiver. inherent interference. At the same time, because the receiving and transmitting radio frequency local oscillator frequency range is directly related to the selected receiving and transmitting intermediate frequency, so when selecting the intermediate frequency of the receiver and transmitter of TD-SCDMA UE and GSM UE, it should also try to reduce the RF VCO and The coverage of the intermediate frequency VCO, thereby reducing the number of radio frequency VCO and intermediate frequency VCO, in order to achieve the purpose of optimizing the design of the required frequency synthesis circuit. To this end, the following restrictions on selecting the IF of the receiver are given first.

1.更好地抑制接收信号的镜频干扰接收机应选择高中频f_IF，其所选接收机中频f_IF-RX应满足条件：150MHz≤f_IF-RX≤350MHz1. To better suppress the image frequency interference of the received signal, the receiver should choose the high-frequency f_IF , and the selected receiver intermediate frequency f_IF-RX should meet the conditions: 150MHz≤f_IF-RX ≤350MHz

2.中频f_IF-RX应大于接收信号带宽B_i的3/2倍以满足其无三阶互调的要求，即$f_{\mathrm{IF}-\mathrm{RX}}>\frac{3}{2}{B}_i.$其中，B_i为接收射频信号带宽。2. The intermediate frequency f_IF-RX should be greater than 3/2 times of the received signal bandwidth_Bi to meet its requirement of no third-order intermodulation, namely$f_{\mathrm{IF}-\mathrm{RX}}>\frac{3}{2}{B}_i.$ Among them, B_i is the bandwidth of the received radio frequency signal.

3.收机中频f_IF-RX的任意次谐波n×f_IF-RX不应落在接收射频带内，以避免对收信机的固定干扰。即$n\×f_{\mathrm{IF}-\mathrm{RX}}\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{Band}}.$其中，f_RF-RX-Band为接收射频频带；n为任意的正整数。3. Any harmonic n×f_IF-RX of the receiver intermediate frequency_{f IF-RX} should not fall within the receiving radio frequency band to avoid fixed interference to the receiver. Right now$\mathrm{no}\×f_{\mathrm{IF}-\mathrm{RX}}\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{band}}.$ Wherein, f_RF-RX-Band is the receiving radio frequency band; n is any positive integer.

4.参考时钟频率f_R的任意次谐波n×f_R不应落在接收机的射频和中频带内，即$n\×f_R\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{Band}};$$n\×f_R\∉f_{\mathrm{IF}-\mathrm{RX}-\mathrm{Band}}.$其中，f_RF-RX-Band为接收射频频带；f_IF-RX-Band为接收机的中频频带；n为任意的正整数。4. Any harmonic n×f_R of the reference clock frequency f_R should not fall within the RF and IF bands of the receiver, i.e.$\mathrm{no}\×f_R\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{band}};$$\mathrm{no}\×f_R\∉f_{\mathrm{IF}-\mathrm{RX}-\mathrm{band}}.$ Wherein, f_RF-RX-Band is the receiving radio frequency band; f_IF-RX-Band is the intermediate frequency band of the receiver; n is any positive integer.

5.同样，DSP工作时钟速率f_S的任意次谐波n×f_S不应落在接收射频和中频带内，即$n\×f_S\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{Band}};$$n\×f_S\∉f_{\mathrm{IF}-\mathrm{RX}-\mathrm{Band}}.$其中，f_RF-RX-Band为射频接收频带；f_IF-RX-Band为接收中频频带；n为任意的正整数。5. Similarly, any harmonic n×f_S of the DSP operating clock rate f_S should not fall within the receiving radio frequency and intermediate frequency bands, that is,$\mathrm{no}\×f_S\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{band}};$$\mathrm{no}\×f_S\∉f_{\mathrm{IF}-\mathrm{RX}-\mathrm{band}}.$ Wherein, f_RF-RX-Band is the radio frequency receiving frequency band; f_IF-RX-Band is the receiving intermediate frequency frequency band; n is any positive integer.

6.基带ADC的取样时钟速率f_B的任意次谐波n×f_B不应落在接收射频和中频带内，即$n\×f_B\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{Band}};$$n\×f_B\∉f_{\mathrm{IF}-\mathrm{RX}-\mathrm{Band}}.$其中，f_RF-RX-Band为射频接收频带；f_IF-RX-Band为接收中频频带；n为任意的正整数。6. Any harmonic n×f_B of the sampling clock rate f_B of the baseband ADC should not fall within the receiving radio frequency and intermediate frequency bands, that is,$\mathrm{no}\×f_B\∉f_{\mathrm{RF}-\mathrm{RX}-\mathrm{band}};$$\mathrm{no}\×f_B\∉f_{\mathrm{IF}-\mathrm{RX}-\mathrm{band}}.$ Wherein, f_RF-RX-Band is the radio frequency receiving frequency band; f_IF-RX-Band is the receiving intermediate frequency frequency band; n is any positive integer.

中频选择计算流程说明IF Selection Calculation Process Description

根据上述TD-SCDMA/GSM UE接收中频选择的限制条件，通过编程计算则可分别求出TD-SCDMA UE和GSM UE收信机各频段的中频频率的可选取范围。其编程计算的主要流程图如图1所示。According to the restrictive conditions of TD-SCDMA/GSM UE receiving IF selection mentioned above, the selectable range of IF frequency for each frequency band of TD-SCDMA UE and GSM UE receiver can be obtained through programming calculation. The main flow chart of its programming calculation is shown in Figure 1.

编程计算其目的是在(150-350)MHz范围内，步进为1MHz时，判决TD-SCDMA/GSMUE接收中频的可选取值。参见图1。流程图中所列的判决条件从$\&lsqb;f_{\mathrm{IF}-\mathrm{RX}}<\frac{3}{2}{B}_i\&rsqb;$至[n×f_B∈f_IF-RX-Band]均与上述第四条的2--6款所给出的中频选择条件相反。所以，在编程计算流程中，当判决为“Y”时，这是违背了实际所需的中频选择条件，从而确定该中频值不可取，流程将直接进入[f_{IF_RX}＝f_{IF_RX}+1]程序循环；而当编程计算流程中判决为“N”时，则是符合了实际所需的中频选择判决条件，流程将进入下步中频选择条件判决。与上步判决类同，若在第二步编程计算流程中判决为“Y”时，则是违背了实际所需的中频选择判决条件，从而确定该中频值不可取，流程将直接进入[f_{IF_RX}＝f_{IF_RX}+1]程序循环；而当编程计算流程中判决为“N”时，则是符合了实际所需的中频选择判决条件，从而确定应进行下一步判决；周而复始，直至完成[n×f_S∈_{fIF_RX_Band}]判决条件，如仍判决为“N”才能最终确定该中频值可取并输出该值。然后，流程才可进入[f_{IF_RX}＝f_{IF_RX}+1]程序循环。只有当f_{IF_RX}+1＝350；[f_{IF_RX}＜350]流程判决为“N”时，才可结束这次中频从150-350MHz的选择判决。The purpose of programming calculation is to judge the selectable value of TD-SCDMA/GSMUE receiving intermediate frequency in the range of (150-350) MHz, when the step is 1 MHz. See Figure 1. Judgment conditions listed in the flow chart from$\&lsqb;f_{\mathrm{IF}-\mathrm{RX}}<\frac{3}{2}{B}_i\&rsqb;$ Up to [n×f_B ∈ f_IF-RX-Band ] are opposite to the selection conditions of IF given in paragraphs 2-6 of the above-mentioned Article 4. Therefore, in the programming and calculation process, when the judgment is "Y", it violates the actual required IF selection condition, so it is determined that the IF value is not desirable, and the process will directly enter the [f_{IF_RX} = f_{IF_RX} + 1] program loop; and when the judgment is "N" in the programming calculation process, it meets the actual required intermediate frequency selection judgment condition, and the process will enter the next step of intermediate frequency selection condition judgment. Similar to the judgment in the previous step, if the judgment is "Y" in the second step of the programming calculation process, it violates the actual required judgment condition for intermediate frequency selection, thus determining that the intermediate frequency value is not desirable, and the process will directly enter [f_{IF_RX} = f_{IF_RX} + 1] program cycle; and when the judgment in the programming calculation process is "N", it is in line with the actual required intermediate frequency selection judgment conditions, so that it is determined that the next step should be judged; it goes round and round until the completion of [n × f_S ∈_{fIF_RX_Band} ] Judgment condition, if it is still judged as "N", it can finally determine that the intermediate frequency value is acceptable and output this value. Then, the process can enter the [f_{IF_RX} =f_{IF_RX} +1] program loop. Only when f_{IF_RX} + 1 = 350; [f_{IF_RX} < 350] is judged as "N", can the selection decision of the intermediate frequency from 150-350MHz be ended.

在图1流程图的基础上，只要根据TD-SCDMA UE在1880-1920MHz，2010-2025MHz，2400-2500MHz频段和GSM UE在935-960MHz频段接收机中频选择的具体要求即可对中频可选取值进行计算。On the basis of the flow chart in Figure 1, the intermediate frequency can be selected according to the specific requirements of TD-SCDMA UE in the 1880-1920MHz, 2010-2025MHz, 2400-2500MHz frequency band and GSM UE in the 935-960MHz frequency band. value is calculated.

1.当TD-SCDMA UE接收机在1880-1920MHz频段工作时，若接收机采用外差方案，则射频VCO的频率范围应为[(1880-1920)+f_IF-TSM-A]MHz。根据上述TD-SCDMA/GSM UE接收中频选择的限制条件(1)-(6)，通过编程计算得出此时接收中频f_IF-TSM-A的可选取范围，其具体计算流程图请见图2，其计算结果请见表1。1. When the TD-SCDMA UE receiver works in the 1880-1920MHz frequency band, if the receiver adopts the heterodyne scheme, the frequency range of the RF VCO should be [(1880-1920)+f_IF-TSM-A ]MHz. According to the restriction conditions (1)-(6) of TD-SCDMA/GSM UE receiving IF selection above, the selectable range of receiving IF f_IF-TSM-A is obtained through programming calculation, and the specific calculation flow chart is shown in Fig. 2. Please refer to Table 1 for the calculation results.

                                                                       表1  单位：MHzTable 1 Unit: MHz

    150 150     151 151     152 152     153 153     154 154     155 155     161 161     162 162     163 163     165 165     166 166     167 167     168 168     170 170     175 175     176 176     177 177     178 178     179 179     180 180     181 181     183 183     184 184     185 185     186 186     187 187     193 193     194 194     196 196     197 197     198 198     199 199     200 200     201 201     202 202     203 203     204 204     205 205     206 206     207 207     214 214     215 215     216 216     217 217     218 218     219 219     220 220     222 222     223 223     224 224     225 225     226 226     227 227     228 228     229 229     230 230     231 231     232 232     233 233     241 241     242 242     243 243     244 244     248 248     249 249     250 250     251 251     252 252     253 253     254 254     255 255     256 256     257 257     258 258     259 259     261 261     262 262     263 263     264 264     265 265     266 266     267 267     268 268     275 275     276 276     277 277     278 278     279 279     280 280     281 281     282 282     283 283     284 284     285 285     286 286     287 287     288 288     289 289     290 290     291 291     292 292     293 293     294 294     295 295     296 296     297 297     298 298     299 299     300 300     301 301     302 302     303 303     304 304     305 305     306 306     307 307     308 308     309 309     310 310     311 311     312 312     313 313     321 321     322 322     323 323     324 324     325 325     326 326     329 329     330 330     331 331     332 332     333 333     334 334     335 335     336 336     337 337     338 338     339 339     340 340     341 341     342 342     343 343     344 344     345 345     346 346     347 347     348 348     349 349     350 350

2.当TD-SCDMA UE接收机在2010-2025MHz频段工作时，若接收机采用外差方案，则射频VCO的频率范围应为[(2010-2025)+f_IF-TSM-B]MHz。根据上述TD-SCDMA/GSM UE接收中频选择的限制条件(1)-(6)，通过编程计算得出此时接收中频f_IF-TSM-B的可选取范围，其具体计算流程图请见图3，其计算结果请见表2。2. When the TD-SCDMA UE receiver works in the 2010-2025MHz frequency band, if the receiver adopts the heterodyne scheme, the frequency range of the radio frequency VCO should be [(2010-2025)+f_IF-TSM-B ]MHz. According to the restriction conditions (1)-(6) of TD-SCDMA/GSM UE receiving IF selection mentioned above, the selectable range of receiving IF f_IF-TSM-B is obtained through programming calculation, and the specific calculation flow chart is shown in Fig. 3. Please refer to Table 2 for the calculation results.

                                                                          表2  单位：MHzTable 2 Unit: MHz

    150 150     151 151     152 152     153 153     154 154     157 157     158 158     159 159     160 160     161 161     162 162     163 163     165 165     166 166     167 167     170 170     171 171     172 172     173 173     174 174     175 175     176 176     177 177     178 178     179 179     180 180     181 181     185 185     186 186     187 187     188 188     189 189     190 190     191 191     192 192     193 193     194 194     196 196     197 197     198 198     199 199     200 200     203 203     204 204     205 205     206 206     207 207     209 209     210 210     211 211     212 212     213 213     214 214     215 215     216 216     217 217     218 218     219 219     220 220     222 222     223 223     226 226     227 227     228 228     229 229     230 230     231 231     232 232     233 233     235 235     236 236     237 237     238 238     239 239     240 240     241 241     242 242     243 243     244 244     248 248     249 249     250 250     251 251     254 254     255 255     256 256     257 257     258 258     259 259     261 261     262 262     263 263     264 264     265 265     266 266     267 267     268 268     269 269     270 270     271 271     272 272     273 273     274 274     275 275     276 276     277 277     278 278     279 279     280 280     281 281     282 282     283 283     284 284     285 285     286 286     287 287     290 290     291 291     292 292     293 293     294 294     295 295     296 296     297 297     298 298     299 299     300 300     301 301     302 302     303 303     304 304     305 305     306 306     307 307     308 308     309 309     310 310     311 311     312 312     313 313     314 314     315 315     316 316     31 7 31 7     318 318     319 319     320 320     321 321     322 322     323 323     324 324     325 325     326 326     329 329     330 330     331 331     332 332     333 333     334 334     338 338     339 339     340 340     341 341     342 342     343 343     344 344     345 345     346 346     347 347     348 348     349 349     350 350

3.当TD-SCDMA UE接收机在2300-2400MHz频段工作时，若接收机采用内差方案，则射频VCO的频率范围应为[(2300-2400)-f_IF-TSM-C]MHz。根据上述TD-SCDMA/GSM UE接收中频选择的限制条件(1)-(6)，通过编程计算得出此时接收中频f_IF-TSM-C的可选取范围，其具体计算流程图请见图4，其计算结果请见表3。3. When the TD-SCDMA UE receiver works in the 2300-2400MHz frequency band, if the receiver adopts the internal difference scheme, the frequency range of the radio frequency VCO should be [(2300-2400)-f_IF-TSM-C ]MHz. According to the restriction conditions (1)-(6) of TD-SCDMA/GSM UE receiving IF selection above, the selectable range of receiving IF f_IF-TSM-C can be obtained through programming calculation, and the specific calculation flow chart is shown in Fig. 4. Please refer to Table 3 for the calculation results.

                                                                       表3  单位：MHzTable 3 Unit: MHz

    151 151     152 152     153 153     161 161     162 162     163 163     172 172     173 173     174 174     175 175     176 176     185 185     186 186     187 187     188 188     189 189     190 190     191 191     201 201     202 202     203 203     204 204     205 205     206 206     207 207     209 209     219 219     220 220     222 222     223 223     224 224     225 225     226 226     227 227     228 228     229 229     241 241     242 242     243 243     244 244     248 248     249 249     250 250     251 251     252 252     253 253     254 254     255 255     267 267     268 268     269 269     270 270     271 271     272 272     273 273     274 274     275 275     276 276     277 277     278 278     279 279     280 280     281 281     282 282     283 283     284 284     285 285     286 286     287 287     301 301     302 302     303 303     304 304     305 305     306 306     307 307     308 308     309 309     310 310     311 311     312 312     313 313     314 314     315 315     316 316     317 317     318 318     319 319     320 320     321 321     322 322     323 323     324 324     325 325     326 326     343 343     344 344     345 345     346 346     347 347     348 348     349 349     350 350

4.从上述第1、2、3步骤所计算出的f_IF-TSM-A，f_IF-TSM-B，f_IF-TSM-C中，可以求出它们所共有的中频频率点f_IF-TSM-RX。具体f_IF-TSM-Rx可选频点范围请见表4。4. From the f_IF-TSM-A , f_IF-TSM-B , and f_IF-TSM-C calculated insteps 1, 2, and 3 above, the intermediate frequency point f_{IF- TSM-RX} . Please refer to Table 4 for the specific f_IF-TSM-Rx optional frequency range.

                                                                      表4  单位：MHzTable 4 Unit: MHz

    151 151     152 152     153 153     161 161     162 162     163 163     175 175     176 176     185 185     186 186     187 187     203 203     204 204     205 205     206 206     207 207     219 219     220 220     222 222     223 223     226 226     227 227     228 228     229 229     241 241     242 242     243 243     244 244     248 248     249 249     250 250     251 251     254 254     255 255     267 267     268 268     275 275     276 276     277 277     278 278     279 279     280 280     281 281     282 282     283 283     284 284     285 285     286 286     287 287     301 301     302 302     303 303     304 304     305 305     306 306     307 307     308 308     309 309     310 310     311 311     312 312     313 313     321 321     322 322     323 323     324 324     325 325     326 326     343 343     344 344     345 345     346 346     347 347     348 348     349 349     350 350

5.因TD-SCDMA UE的接收和发射频率相同，所以应选取TD-SCDMA UE的发射中频f_{IF-TSM_TX}应与TD-SCDMA UE的接收中频f_IF-TSM-RX相同，即f_{IF-TSM_TX}＝f_IF-TSM-RX＝f_IF-TSM。这样只要TD-SCDMA UE在1880-1920MHz和2010-2025MH频段工作采用变频下边带发射；而2300-2400MHz则采用变频上边带发射。不难算出TD-SCDMA UE发射机所需的射频VCO的频率覆盖范围f_{RF-TSM-VCO-TX}与TD-SCDMA UE收信机所需的射频VCO的频率范围f_{RF-TSM-VCO-RX}是完全一样的。即TD-SCDMA UE收发完全共用一个射频本振频率，这样在收发时隙转换时，射频本振的频率则不需转换。这对保持稳定的接收和发射是非常有利的。5. Since the receiving and transmitting frequencies of TD-SCDMA UE are the same, the transmitting intermediate frequency f_{IF-TSM_TX} of TD-SCDMA UE should be selected to be the same as the receiving intermediate frequency f_IF-TSM-RX of TD-SCDMA UE, that is, f_{IF-TSM_TX} =f_IF-TSM-RX =f_IF-TSM . In this way, as long as the TD-SCDMA UE works in the 1880-1920MHz and 2010-2025MH frequency bands, it adopts frequency conversion lower sideband transmission; while 2300-2400MHz adopts frequency conversion upper sideband transmission. It is not difficult to calculate the frequency coverage f_{RF-TSM-VCO-TX} of the radio frequency VCO required by the TD-SCDMA UE transmitter and the frequency coverage f_{RF-TSM-VCO-RX} of the radio frequency VCO required by the TD-SCDMA UE receiver are exactly the same. That is to say, TD-SCDMA UEs transmit and receive completely share one radio frequency local oscillator frequency, so when the time slots for transmitting and receiving are switched, the frequency of the radio frequency local oscillator does not need to be switched. This is very beneficial for maintaining stable reception and transmission.

6.当GSM UE接收机在935-960MHz频段工作时，若接收机采用外差方案并将射频VCO的本振信号在参与接收下变频前经除2电路分频，则射频本振的频率范围应为2×[(935-960)+f_IF-GSM-RX]MHz。根据上述TD-SCDMA/GSM UE接收中频选择的限制条件(1)-(6)，通过编程计算得出此时接收中频f_IF-GSM-RX的可选取范围，其具体计算流程图请见图5，其计算结果请见表5。6. When the GSM UE receiver works in the 935-960MHz frequency band, if the receiver adopts the heterodyne scheme and the local oscillator signal of the RF VCO is divided by 2 before participating in the receiving down-conversion, the frequency range of the RF local oscillator It should be 2×[(935-960)+f_IF-GSM-RX ]MHz. According to the restriction conditions (1)-(6) of TD-SCDMA/GSM UE receiving IF selection mentioned above, the selectable range of receiving IF f_IF-GSM-RX is obtained through programming calculation, and the specific calculation flow chart is shown in Fig. 5. Please refer to Table 5 for the calculation results.

                                                                        表5  单位：MHzTable 5 Unit: MHz

    151 151     152 152     153 153     154 154     155 155     161 161     162 162     164 164     165 165     166 166     167 167     168 168     170 170     171 171     172 172     173 173     174 174     175 175     177 177     178 178     179 179     180 180     181 181     183 183     184 184     185 185     186 186     193 193     194 194     196 196     197 197     198 198     199 199     200 200     201 201     203 203     204 204     205 205     206 206     207 207     209 209     210 210     211 211     212 212     213 213     214 214     216 216     217 217     218 218     219 219     220 220     222 222     223 223     224 224     225 225     226 226     227 227     228 228     229 229     230 230     231 231     232 232     233 233     241 241     242 242     243 243     244 244     245 245     246 246     248 248     249 249     250 250     251 251     252 252     253 253     254 254     255 255     256 256     257 257     258 258     259 259     261 261     262 262     263 263     264 264     265 265     266 266     267 267     268 268     269 269     270 270     271 271     272 272     273 273     274 274     275 275     276 276     277 277     278 278     279 279     280 280     281 281     282 282     283 283     284 284     285 285     286 286     287 287     288 288     289 289     290 290     291 291     292 292     293 293     294 294     295 295     296 296     297 297     298 298     299 299     300 300     301 301     302 302     303 303     304 304     305 305     306 306     307 307     305 305     309 309     310 310     311 311     321 321     322 322     323 323     324 324     325 325     326 326     327 327     328 328     329 329     330 330     331 331     332 332     333 333     334 334     335 335     336 336     337 337     338 338     339 339     340 340     341 341     342 342     343 343     344 344     345 345     346 346     347 347     348 348     349 349     350 350

7.若选取GSM UE的发射中频f_{IF-GSM_TX}较GSM UE的接收中频f_IF-GSM-RX高45MHz，即f_{IF-GSM_TX}＝(f_IF-GSM-RX+45)MHz。若这时发射时采用变频下边带发射，并对射频VCO的发本振信号在参与发信变频前需经除2电路分频，则不难算出GSM UE发射机所需的射频VCO的频率范围f_{RF-GSM-VCO-TX}＝2×[(890-915)+f_{IF-GSM_TX}]MHz＝2×[(935-960)+f_IF-GSM-RX]。这与GSM UE收信机所需的射频本振的频率范围完全相同。则GSM UE接收和发射的射频本振同样实现了共用。7. If the transmit intermediate frequency f_{IF-GSM_TX} of the GSM UE is selected to be 45 MHz higher than the receive intermediate frequency f_IF-GSM-RX of the GSM UE, that is, f_{IF-GSM_TX} = (f_IF-GSM-RX + 45) MHz. If the frequency conversion lower sideband transmission is used for transmission at this time, and the local oscillator signal of the RF VCO needs to be divided by 2 before participating in the frequency conversion of the signal, then it is not difficult to calculate the frequency range of the RF VCO required by the GSM UE transmitter f_{RF-GSM-VCO-TX} = 2×[(890-915)+f_IF-GSM-TX ] MHz=2×[(935-960)+f_IF-GSM-RX ]. This is exactly the same frequency range as the RF LO required for GSM UE receivers. Then the radio frequency local oscillators of the GSM UE receiving and transmitting are also shared.

8.不论是TD-SCDMA UE或是GSM UE，因在进行正交调制或正交解调时，其所需中频本振信号都需经除2电路分频，所以若选择TD-SCDMA UE的收发中频为f_IF-TSM；GSMUE的收发中频为f_IF-GSM。则TD-SCDMA/GSM UE所需的中频本振频率的覆盖范围则为f_IF-VCO＝2×(f_IF-TSM_f_IF-GSM)8. Regardless of whether it is TD-SCDMA UE or GSM UE, when performing orthogonal modulation or orthogonal demodulation, the required intermediate frequency local oscillator signal needs to be divided by 2 circuits, so if you choose TD-SCDMA UE The transmitting and receiving intermediate frequency is f_IF-TSM ; the transmitting and receiving intermediate frequency of GSMUE is f_IF-GSM . Then the TD-SCDMA/GSM UE needs the coverage of the IF local oscillator frequency as f_IF-VCO =2×(f_IF-TSM _f_IF-GSM )

9.若从表4中选取TD-SCDMA的接收中频f_IF-TSM-Rx为186MHz，则不难算出为同时满足TD-SCDMA UE在1880-1920MHz；2010-2025MHz；2300-2400MHz接收和发射的需要，其射频VCO的频率范围应为2066-2214MHz。9. If the receiving intermediate frequency f_IF-TSM-Rx of TD-SCDMA is selected from Table 4 as 186MHz, it is not difficult to calculate the requirements for TD-SCDMA UE to receive and transmit at 1880-1920MHz; 2010-2025MHz; 2300-2400MHz at the same time. If necessary, the frequency range of its RF VCO should be 2066-2214MHz.

10.同样，若在表5中选取GSM的接收中频为165MHz，则不难算出为同时满足GSM在890-915MHz频段发射和935-960MHz频段接收的需要，其射频VCO的频率范围应为2110-2250MHz。10. Similarly, if the receiving intermediate frequency of GSM is selected as 165MHz in Table 5, it is not difficult to calculate that the frequency range of the RF VCO should be 2110- 2250MHz.

11.从第9、第10条的计算结果不难看出，为同时满足TD-SCDMA/GSM UE收发工作的需要，其射频VCO的频率覆盖应为2066-2250MHz。很明显2066-2250MHz只有184MHz的覆盖范围，这正是说明TD-SCDMA/GSM UE完全可以共用一个射频VCO。11. From the calculation results of Articles 9 and 10, it is not difficult to see that in order to meet the needs of TD-SCDMA/GSM UE transceiver work at the same time, the frequency coverage of its radio frequency VCO should be 2066-2250MHz. Obviously, 2066-2250MHz only has a coverage of 184MHz, which just means that TD-SCDMA/GSM UE can completely share a radio frequency VCO.

12.同样，从第9、第10条中得知TD-SCDMA和GSM接收中频分别为186MHz和165MHz，则不难求出TD-SCDMA/GSM共用的中频VCO的频率覆盖应为330-372MHz，这正是说明TD-SCDMA/GSM UE同样可以共用一个中频VCO。12. Similarly, from Articles 9 and 10, it is known that the receiving intermediate frequencies of TD-SCDMA and GSM are 186MHz and 165MHz respectively, so it is not difficult to find out that the frequency coverage of the intermediate frequency VCO shared by TD-SCDMA/GSM should be 330-372MHz, This just means that TD-SCDMA/GSM UE can also share an IF VCO.

上述的方法已应用在TD-SCDMA/GSM UE的试验样机之中，实践证明切实有效。The above-mentioned method has been applied in the test prototype of TD-SCDMA/GSM UE, and it has been proved effective in practice.

Claims (10)

Translated fromChinese

1.一种TD-SCDMA/GSM UE双模多频段收发信机的中频频率选择方法，其特征在于选择接收机中频的限制条件为：1. a kind of IF frequency selection method of TD-SCDMA/GSM UE dual-mode multi-band transceiver, it is characterized in that the restrictive condition of selecting receiver IF is:(1).接收机选择高中频f_IF，其所选接收机中频f_IF-RX应满足条件：150MHz≤f_IF-RX≤350MHz；(1). The receiver selects the intermediate frequency f_IF , and the selected receiver intermediate frequency f_IF-RX should meet the conditions: 150MHz≤f_IF-RX ≤350MHz;(2).选择接收中频f_IF-RX应大于接收信号带宽B_i的3/2倍以满足其无三阶互调的要求，即$f_{\mathrm{IF}-\mathrm{RX}}>\frac{3}{2}{B}_i;$其中，B_i为接收射频信号带宽；(2). Selecting the receiving intermediate frequency f_IF-RX should be greater than 3/2 times of the receiving signal bandwidth B_i to meet its requirement of no third-order intermodulation, that is$f_{\mathrm{IF}-\mathrm{RX}}>\frac{3}{2}{B}_i;$ Wherein, B_i is the bandwidth of the received radio frequency signal;(3).接收机中频f_IF-RX的任意次谐波n×f_IF-RX不应落在接收射频带内，以避免对收信机的固定干扰。即$n\&times;f_{\mathrm{IF}-\mathrm{RX}}\&NotElement;f_{\mathrm{RF}-\mathrm{RX}-\mathrm{Band}};$其中，f_RF-RX-Band为接收射频频带；n为任意的正整数；(3). Any harmonic n×f_IF-RX of the receiver intermediate frequency f_IF-RX should not fall within the receiving radio frequency band to avoid fixed interference to the receiver. Right now$\mathrm{no}\&times;f_{\mathrm{IF}-\mathrm{RX}}\&NotElement;f_{\mathrm{RF}-\mathrm{RX}-\mathrm{band}};$ Wherein, f_RF-RX-Band is the receiving radio frequency band; n is any positive integer;(4).参考时钟频率f_R的任意次谐波n×f_R不应落在接收机的射频和中频带内，即${n\&times;f_R\&NotElement;f}_{\mathrm{RF}-\mathrm{RX}-\mathrm{Band}};$$n\&times;f_R\&NotElement;f_{\mathrm{IF}-\mathrm{RX}-\mathrm{Band}};$其中，f_RF-RX-Band为接收射频频带：f_IF-RX-Band为接收机的中频频带；n为任意的正整数；(4). Any harmonic n×f_R of the reference clock frequency f_R should not fall within the radio frequency and intermediate frequency bands of the receiver, that is${\mathrm{no}\&times;f_R\&NotElement;f}_{\mathrm{RF}-\mathrm{RX}-\mathrm{band}};$$\mathrm{no}\&times;f_R\&NotElement;f_{\mathrm{IF}-\mathrm{RX}-\mathrm{band}};$ Wherein, f_RF-RX-Band is the receiving radio frequency band: f_IF-RX-Band is the intermediate frequency band of the receiver; n is any positive integer;(5).工作时钟速率f_S的任意次谐波n×f_S不应落在接收射频和中频带内，即$n\&times;f_S\&NotElement;f_{\mathrm{RF}-\mathrm{RX}-\mathrm{Band}};$$n\&times;f_S\&NotElement;f_{\mathrm{IF}-\mathrm{RX}-\mathrm{Band}};$其中，f_RF-RX-Band为射频接收频带；f_IF-RX-Band为(5). Any harmonic n×f_S of the working clock rate f_S should not fall within the receiving radio frequency and intermediate frequency bands, that is$\mathrm{no}\&times;f_S\&NotElement;f_{\mathrm{RF}-\mathrm{RX}-\mathrm{band}};$$\mathrm{no}\&times;f_S\&NotElement;f_{\mathrm{IF}-\mathrm{RX}-\mathrm{band}};$ Among them, f_RF-RX-Band is the radio frequency receiving frequency band; f_IF-RX-Band is接收中频频带；n为任意的正整数；Receiving the intermediate frequency band; n is any positive integer;(6).基带ADC的取样时钟速率f_B的任意次谐波n×f_B不应落在接收射频和中频带内，即$n\&times;f_B\&NotElement;f_{\mathrm{RF}-\mathrm{RX}-\mathrm{Band}};$$n\&times;f_B\&NotElement;f_{\mathrm{IF}-\mathrm{RX}-\mathrm{Band}};$其中，f_RF-RX-Band为射频接收频带；(6). Any harmonic n×f_B of the sampling clock rate f_B of the baseband ADC should not fall within the receiving radio frequency and intermediate frequency bands, that is$\mathrm{no}\&times;f_B\&NotElement;f_{\mathrm{RF}-\mathrm{RX}-\mathrm{band}};$$\mathrm{no}\&times;f_B\&NotElement;f_{\mathrm{IF}-\mathrm{RX}-\mathrm{band}};$ Wherein, f_RF-RX-Band is the radio frequency receiving frequency band;f_IF-RX-Band为接收中频频带；n为任意的正整数。f_IF-RX-Band is the receiving intermediate frequency band; n is any positive integer.2.如权利要求1所述的方法，其特征在于当TD-SCDMA UE接收机在1880-1920MHz频段工作时，若接收机采用外差方案，则射频VCO的频率范围应为[(1880-1920)+f_IF-TSM-A]MHz，根据TD-SCDMA/GSM UE接收中频选择的限制条件1)-6)，通过编程计算得出此时接收中频f_IF-TSM-A的可选取范围。2. method as claimed in claim 1 is characterized in that when TD-SCDMA UE receiver works in 1880-1920MHz frequency band, if receiver adopts heterodyne scheme, then the frequency range of radio frequency VCO should be [(1880-1920 )+f_IF-TSM-A ]MHz, according to TD-SCDMA/GSM UE receiving IF selection restriction conditions 1)-6), the selectable range of receiving IF f_IF-TSM-A is calculated by programming.3.如权利要求1所述的方法，其特征在于当TD-SCDMA UE接收机在2010-2025MHz频段工作时，若接收机采用外差方案，则射频VCO的频率范围应为[(2010-2025)+f_IF-TSM-B]MHz，根据TD-SCDMA/GSM UE接收中频选择的限制条件(1)-(6)，通过编程计算得出此时接收中频f_IF-TSM-B的可选取范围。3. The method according to claim 1, wherein when the TD-SCDMA UE receiver works in the 2010-2025MHz frequency band, if the receiver adopts a heterodyne scheme, the frequency range of the radio frequency VCO should be [(2010-2025 )+f_IF-TSM-B ]MHz, according to the restriction conditions (1)-(6) of TD-SCDMA/GSM UE receiving intermediate frequency selection, the optional receiving intermediate frequency f_IF-TSM-B can be calculated by programming scope.4.如权利要求1所述的方法，其特征在于当TD-SCDMA/GSM UE工作在TDD模式，在2300-2400MHz频段接收时，接收机采用内差方案，求出符合在该频段工作的接收中频f_IF-TSM-C。4. The method according to claim 1, wherein when the TD-SCDMA/GSM UE works in the TDD mode and receives in the 2300-2400MHz frequency band, the receiver adopts the inner difference scheme to obtain the receiving signal that meets the requirements of the frequency band. Intermediate frequency f_IF-TSM-C .5.如权利要求1所述的方法，其特征在于当TD-SCDMA/GSM UE工作在TDD模式，在1920-1980MHz，2010-2025MHz，2300-2400MHz任意频段接收工作，TD-SCDMA UE中频f_IF-TSM的选择应在f_IF-TSM-A，f_IF-TSM-B和f_IF-TSM-C共同的覆盖范围内。5. the method for claim 1 is characterized in that when TD-SCDMA/GSM UE works in TDD pattern, at 1920-1980MHz, 2010-2025MHz, 2300-2400MHz arbitrary frequency band receives work, TD-SCDMA UE intermediate frequency f_IF - The choice of_TSM should be within the common coverage of_fIF-TSM-A ,_fIF-TSM-B and_fIF-TSM-C .6.如权利要求1所述的方法，其特征在于当TD-SCDMA/GSM UE工作在FDD模式，在935-960MHz频段接收时，接收机采用外差方案，求出符合在该频段工作的接收中频f_IF-GSM，这正是GSM UE中频的选择范围。6. The method according to claim 1, characterized in that when the TD-SCDMA/GSM UE works in the FDD mode and receives in the 935-960MHz frequency band, the receiver adopts a heterodyne scheme to obtain the receiving signal that meets the requirements of the frequency band. The intermediate frequency f_IF-GSM is the selection range of the GSM UE intermediate frequency.7.如权利要求1所述的方法，其特征在于当TD-SCDMA/GSM UE工作在TDD模式，在1920-1980MHz，2010-2025MHz，2300-2400MHz任意频段接收工作，同时符合权利要求1所述的收信机中频选择限制条件和计算方法，最终TD-SCDMA UE中频f_IF-TSM的选择应在f_IF-TSM-A，f_IF-TSM-B和f_IF-TSM-C共同的覆盖范围内。7. The method according to claim 1, characterized in that when the TD-SCDMA/GSM UE works in TDD mode, it can receive work in any frequency band of 1920-1980MHz, 2010-2025MHz, 2300-2400MHz, and meet the requirements of claim 1 The receiver IF selection constraints and calculation methods, the final selection of TD-SCDMA UE IF f_IF-TSM should be within the common coverage of f_IF-TSM-A , f_IF-TSM-B and f_IF-TSM-C Inside.8.如权利要求1所述的方法，其特征在于当TD-SCDMA/GSM UE工作在FDD模式，在935-960MHz频段接收时，接收机采用外差方案，求出符合在该频段工作的接收中频f_IF-GSM，这正是GSM UE中频的选择范围。8. The method according to claim 1, characterized in that when the TD-SCDMA/GSM UE works in the FDD mode and receives in the 935-960MHz frequency band, the receiver adopts a heterodyne scheme to obtain the receiving signal that meets the requirements of the frequency band. The intermediate frequency f_IF-GSM is the selection range of the GSM UE intermediate frequency.9.如权利要求1所述的方法，其特征在于当TD-SCDMA/GSM UE工作在TDD模式，在1920-1980MHz，2010-2025MHz，2300-2400MHz任意频段发射工作时，发射中频与接收中频相同。9. The method according to claim 1, characterized in that when the TD-SCDMA/GSM UE works in the TDD mode and transmits at 1920-1980MHz, 2010-2025MHz, or 2300-2400MHz in any frequency band, the transmitting intermediate frequency is the same as the receiving intermediate frequency .10.如权利要求1所述的方法，其特征在于当TD-SCDMA/GSM UE工作在FDD模式，在890-915MHz频段发射工作时，发射中频较接收中频高45MHz。10. The method according to claim 1, wherein when the TD-SCDMA/GSM UE works in the FDD mode and transmits in the 890-915MHz frequency band, the transmitting intermediate frequency is 45MHz higher than the receiving intermediate frequency.

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