Indigital communications, achip is a pulse of adirect-sequence spread spectrum (DSSS) code, such as a pseudo-random noise (PN) code sequence used in direct-sequencecode-division multiple access (CDMA)channel access techniques.

In a binary direct-sequence system, each chip is typically a rectangular pulse of +1 or −1 amplitude, which is multiplied by a data sequence (similarly +1 or −1 representing the messagebits) and by a carrier waveform to make the transmitted signal. The chips are therefore just the bit sequence out of the code generator; they are called chips to avoid confusing them with message bits.^[1]

Thechip rate of a code is the number of pulses per second (chips per second) at which the code is transmitted (or received). The chip rate is larger than thesymbol rate, meaning that onesymbol is represented by multiple chips. The ratio is known as thespreading factor (SF) or processing gain:

${\displaystyle \text{SF}=\frac{\text{chip rate}}{\text{symbol rate}}}$

Orthogonal variable spreading factor (OVSF) is an implementation ofcode-division multiple access (CDMA) where before each signal is transmitted, thesignal is spread over a wide spectrum range through the use of a user's code. Users' codes are carefully chosen to be mutuallyorthogonal to each other.

These codes are derived from an OVSF code tree, and each user is given a different code. An OVSF code tree is a completebinary tree that reflects the construction ofHadamard matrices.

• Baud
• GPS signals

• CDMA basics

This article aboutwireless technology is astub. You can help Wikipedia byexpanding it.

• v
• t
• e

• Code division multiple access
• Wireless stubs

• Articles with short description
• Short description matches Wikidata
• All stub articles