FX919B Datasheet, PDF (44/47 Pages) CML Microcircuits – Excellent Radio Fading Performance

4-Level FSK Modem Data Pump
FX919B
1E-1
1E-2
1E-3
BER
1E-4
BER with FEC
BER without FEC
1E-5
1E-6
8
9
10
11
12
13
14
15
16
S/N dB (Noise in 2 x Symbol Rate Bandwidth)
Figure 24 Typical Bit Error Rate With and Without FEC
Measured under nominal working conditions, LEVRES bits set to ‘Level Track’ or ‘Slow Peak Detect’ and
PLLBW bits set to ‘Medium’ or ‘Narrow’ Bandwidth, Command Register TXIMP bit set to 0 or 1 (same for Tx
and Rx devices), with pseudo-random data.
Note: S/N calculated as 20 × LOG10( Signal Voltage ÷ Noise Voltage)
Where Signal Voltage is the measured rms. voltage of a random 4-level signal.
Noise Voltage is the rms. voltage of a flat Gaussian noise signal having a bandwidth from a few
Hz to twice the symbol rate (e.g. to 9600Hz when measuring a 4800 symbol/sec system).
Both signals are measured at the same point in the test circuit.
© 1997 Consumer Microcircuits Limited
44
D/919B/1