Apparatus and method for self-testing a component for signal recovery

1. A method comprising:

providing a receive signal to receive circuitry using a multiplexer when the receive signal has been selected;

performing signal recovery using a component of the receive circuitry;

generating, using BIST (Built-in Self-Test) circuitry, a stress signal that simulates an imperfect signal received over a communication channel;

providing the stress signal to the receive circuitry using the multiplexer when the stress signal has been selected in order to test the component; and

determining, using a detector, at least one condition indicative of whether the component is operating properly with the stress signal.

2. The method of claim 1 , further comprising:

generating a transmit signal using transmit circuitry;

wherein generating the stress signal comprises the BIST circuitry transforming the transmit signal into the stress signal.

3. The method of claim 2 , wherein the component of the receive circuitry is an adaptive equalizer.

4. The method of claim 3 , further comprising:

recovering data following the signal recovery using CDR (Clock and Data Recovery) circuitry;

wherein the at least one condition indicative of whether the adaptive equalizer is operating properly comprises whether recovered data from the CDR circuitry matches original data from the transmit signal.

5. A method comprising:

providing signal recovery using a component of receive circuitry;

testing the component using a stress signal generated by BIST (Built-in Self-Test) circuitry to simulate an imperfect signal received over a communication channel; and

determining, using a detector, at least one condition indicative of whether the component is operating properly with the stress signal;

wherein generating the stress signal comprises:

generating a transmit signal using transmit circuitry provided in the circuit; and

transforming, using the BIST circuitry, the transmit signal into the stress signal by filtering the transmit signal with a filter provided in the BIST circuitry.

6. The method of claim 5 , wherein the filter is a low-pass filter configured to attenuate high frequencies in the transmit signal.

7. The method of claim 5 , wherein the filter is an analog filter.

8. The method of claim 5 , wherein the filter is a digital filter.

9. The method of claim 5 , wherein the filter is programmable to different configurations for varying the stress signal.

10. The method of claim 5 , wherein the component of the receive circuitry is a non-adaptive equalizer or a fixed filter designed to compensate for ISI (Inter-Symbol Interference).

11. A method comprising:

performing signal recovery using a component of receive circuitry;

testing the component using a stress signal generated by BIST (Built-in Self-Test) circuitry to simulate an imperfect signal received over a communication channel; and

determining, using a detector, at least one condition indicative of whether the component is operating properly with the stress signal;

wherein generating the stress signal comprises:

generating a transmit signal using transmit circuitry provided in the circuit; and

transforming, using the BIST circuitry, the transmit signal into the stress signal by introducing noise into the transmit signal with a noise generator provided in the BIST circuitry.

12. The method of claim 11 , wherein:

the noise generator is configured to reduce SNR (Signal to Noise Ratio) to a predefined level.

13. The method of claim 11 , wherein:

the noise generator is programmable for varying noise in the stress signal.

14. The method of claim 11 , wherein the component of the receive circuitry is a non-adaptive equalizer or a fixed filter designed to compensate for ISI (Inter-Symbol Interference).

15. A method comprising:

performing signal recovery using a component of receive circuitry comprising a component configured for signal recovery;

testing the component with a stress signal generated by BIST (Built-in Self-Test) circuitry to simulate an imperfect signal received over a communication channel; and

determining, using a detector, at least one condition indicative of whether the component is operating properly with the stress signal;

wherein generating the stress signal comprises:

generating a transmit signal using transmit circuitry provided in the circuit;

selecting one of a plurality of transformation modules to generate the stress signal for the component; and

transforming, using the transformation module that has been selected, the transmit signal into the stress signal.

16. The method of claim 15 , wherein each transformation module comprises at least one of (i) a filter and (ii) a noise generator.

17. The method of claim 15 , wherein the transformation modules vary in configuration thereby allowing different possibilities for the stress signal.

18. The method of claim 15 , wherein the component of the receive circuitry is a non-adaptive equalizer or a fixed filter designed to compensate for ISI (Inter-Symbol Interference).

19. A circuit comprising:

receive circuitry comprising a component configured for signal recovery;

transmit circuitry configured for generating a transmit signal;

BIST (Built-in Self-Test) circuitry configured for testing the component with a stress signal that is generated to simulate an imperfect signal received over a communication channel, the BIST circuitry being configured to transform the transmit signal into the stress signal by filtering the transmit signal; and

a detector configured for determining at least one condition indicative of whether the component is operating properly with the stress signal.

20. The circuit of claim 19 , wherein the BIST circuitry is configured for filtering the transmit signal by attenuating high frequencies in the transmit signal.