Patent ID: 7633878

Claim:
In a serial communications receiver, a method for selecting loss of signal (LOS) criteria, the method comprising: a receiver receiving a serial stream of digital data; a LOS manager selecting LOS criteria from a group consisting of a “signal detect” signal received from a source transmitting the serial stream of digital data, a run length test, a signal strength (voltage amplitude) test, harmonic band detection test, and a received data clock test; a LOS measurement circuit comparing the serial stream of digital data to the selected LOS criteria; in response to the serial stream of digital data failing to meet the selected LOS criteria, the LOS manager generating a LOS signal; and, wherein selecting the received data clock test includes: accepting the serial stream of data at a phase detector; generating a voltage controlled oscillator (VCO) frequency in response to recovering a serial stream data clock rate; comparing a measurement of a serial stream data clock rate with the VCO frequency, where the measurement is selected from a group consisting of phase and frequency; and, verifying that the measurement is within a predetermined tolerance.