FX651 Datasheet, PDF (13/16 Pages) CML Microcircuits – SPM and Security Subsystem

SPM and Security Subsystem
System Timings (See also Table 1 on next page)
FX651
(a) SPM (12kHz) channel. Toneburst and tonegaps less than the response and de-response delays
are ignored.
(b) Security tone (18kHz) channel. The response and de-response times are short to enable the
device to recognise the short ON-OFF bursts (20ms each).
(c) Transmit Mode. TXOP is modulated by the NRZ DATA pin. An 18kHz toneburst represents logic
"0" and "no tone" represents logic "1". Data packets with symbol periods greater than or equal to
6ms can be transmitted.
Figure 3 System Timing Diagrams
© 1997 Consumer Microcircuits Limited
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D/651/4