AT48802 Datasheet, PDF (1/23 Pages) ATMEL Corporation – Spread- Spectrum Signal Processor Integrated Circuit

AT48802
Features
Two Independent PN (Pseudo-Random Noise) Generators
• _{Programmable R7 (128) to R13 (8,192) PN Sequence Lengths}
• _{Programmable Tau-Dither Amplitude}
• _{Programmable PN Phase Adjustment to 1/16 Chip}
• _{Correlation Acquisition Interface}
• _{Programming Register Control}
• _{Microcontroller Compatible Bus Interface}
• _{Patent-Pending Frequency Diversity}
•• _{Low Speed Link Data Path for Supervisory and Setup Functions}
Description
The AT48802 Spread-Spectrum Signal Processor (SSSP) chip from Atmel handles
all PN code generation, synchronization, and handshaking required for either station
(handset or base station) of a time division duplex direct sequence spread-spectrum
cordless telephone. The AT48802 supports RF spreading and despreading for the
best rejection of interference. In conjunction with a single-chip microcontroller, the
circuit performs the following functions:
• Generates a pseudo-random sequence for spreading the transmitted signal.
• Generates a pseudo-random sequence for despreading in the receiver.
• Generates a sliding phase PN for acquiring synchronization with an incoming
signal.
• Controls receive signal strength measurement timing for correlation peak
detection.
• Operates a tau-dither tracking loop, with adaptive threshold, to maintain
synchronization with the incoming signal.
• Controls transmit keying antenna switching for time-division duplexing.
Pin Configuration
(continued)
64 Lead PQFP
Spread-
Spectrum
Signal
Processor
Integrated
Circuit
Preliminary
0624A
2-1