BPC is the callsign of atime signal broadcasting from the BPC Shangqiu Low-Frequency Time-Code Radio Station, cooperatively constructed by theNational Time Service Center of theChinese Academy of Sciences and Xi'an Gaohua Technology Co., Ltd.[1], beginning April 25, 2002.

BPC transmits a time signal on 68.5 kHz, which can be used for synchronizing radio controlled clocks. The transmission site is situated nearShangqiu,Henan Province^[1] at34°27′25″N115°50′13″E / 34.457°N 115.837°E /34.457; 115.837.^[2]

BPC broadcasts at 90 kW for 20 hours per day, with a 4-hour break from 05:00–09:00China Standard Time daily (21:00–01:00 UTC).^[3] BPC includes both a conventionalamplitude-modulated time code transmitted during the first 400  of each second, and an additionalphase-modulated spread-spectrum time code transmitted during the last 600 ms of each second, about which little is known.^[4]

BPC transmits the time every 20 seconds, using anamplitude-modulated binary code sent at 2 bits per second. Each 20-second block encodes theChina Standard Time of the beginning of that block.^[5]

To encode each pair of bits, the transmitter is reduced by 10dB (to 10% of normal power) at the beginning of each second, and restored to full power after a multiple of 0.1 seconds. The duration of the reduction encodes the bits, as follows:

If there is no signal reduction at all, that is a special marker which marks the beginning of the time code.

Note that the bits sent in the same second as the parity bits are not parity-checked.

• 低频时码授时, from the National Time Service Center, Chinese Academy of Sciences

This article related to radio communications is astub. You can help Wikipedia byexpanding it.

• v
• t
• e

• Time signal radio stations
• Radio stations established in 2002
• 2002 establishments in China
• Radio communications stubs

• Pages using gadget WikiMiniAtlas
• CS1 Chinese-language sources (zh)
• Articles with short description
• Short description is different from Wikidata
• Coordinates on Wikidata
• All stub articles