SP2-433-160 Datasheet, PDF (26/27 Pages) Radiometrix Ltd – UHF SpacePort Transceiver

APPENDIX - D
The FRPC as a control IC
Clock frequency
All timings within the SP2 (except sleep) are determined by the clock frequency. The standard
frequency is 20.48MHz and all timings unless explicitly stated otherwise, assume this clock frequency.
The
data
rate
=
f _clk
128
bits/s
( i.e. 160kbit/s for Fclk=20.48MHz)
Clock accuracy
The SP2 uses synchronous data transmission and requires an accurate reference clock. In the worst
case , max. preamble and packet length, the allowable bit rate timing error between transmitter and
receiver is 0.2 bits in 1000 bits, i.e. +/-200ppm total or +/-100ppm at each end.
Bit Time
=
128
f _xtal
Hz
i.e. 20.48MHz crystal = 6.25µs PER BIT
Accuracy, temp drifts MUST KEEP X-TAL +/- 100ppm of nominal
Radiometrix Ltd, SP2 data sheet
page 26