CMX7164 Datasheet, PDF (128/146 Pages) CML Microcircuits – Automatic frame sync detect

CMX7164 Multi Mode Modem
CMX7164
11.5 7164FI-6.x Typical Receive Performance
11.5.1 Signal-to-Noise Performance
Signal-to-noise performance was measured by sending 200 bursts of a known PRBS sequence. Each
burst contained 800 bytes, for a total of 160,000 bytes, or 1,280,000 bits. Bit errors were detected by
comparing with the known sequence. A CMX994-based receiver was used for this test. Tx Deviation was
±1.5kHz and the default, narrow channel filter was used.
Figure 110 Signal Level vs BER
11.5.2 Adjacent Channel Performance
Assessment of the adjacent channel rejection (ACR) performance of the modem is normally made in
terms of BER or PER for a given ratio between the wanted signal (on channel) and larger interferer on the
adjacent channel. Detailed measurement methods vary depending on the standards in use, in particular
whether the wanted signal is raised above the sensitivity limit and where the reference is taken. The
figures quoted here are based on the measurement method from EN 300 113. The results are based on
the difference between the interferer (400Hz FM modulation, 1.5kHz deviation) and the power of the
wanted signal for 1.2ksymbols/s.
Channel bandwidth
12.5kHz
25kHz
Adjacent Channel rejection
60dB
70dB
BER
<1%
<1%
The results shown here are typical of what may be achieved with 7164FI-6.x and a typical I/Q radio
receiver with no adjacent channel selectivity provided by receiver RF circuits. Genuine RF receivers
typically provide some adjacent channel selectivity that would make system performance better than the
measured values for the 7164FI-6.x alone. Furthermore, the results observed are not necessarily the
 2015 CML Microsystems Plc
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