Method of test characterization of an analog front end receiver in a communication system

• US 20060141937A1
• Filed: 12/28/2004
• Published: 06/29/2006
• Est. Priority Date: 12/28/2004
• Status: Active Grant

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Creigh, John Lock
• Granted Patent: US 7,460,840 B2
• Time in Patent Office: Days
• US Class Current: 455/67.110
• CPC Class Codes: H04B 17/15 Performance testing
• CPC Class Codes: H04B 17/20 of receivers

Abstract

A multi-port transceiver includes a transmitter and receiver for each port. The invention is a test method and apparatus for testing individual components in the transmit and receive paths. Specifically, the invention includes a method of testing the full range of a programmable gain amplifier (PGA) and an analog to digital converter (ADC) in the receive path of each port. This is accomplished by connecting the transmitter of one port directly to the receiver of a second port, and varying the amplitude of the transmitter over a range of gain settings of the PGA while examining if the dynamic range of the receiver has been exceeded.

Claims

1. In a transceiver having a plurality of ports with each port including a transmitter with variable amplitude and a receiver having a programmable gain amplifier (PGA) and an analog to digital converter (ADC), a method of testing the components of the transceiver, comprising:

(1) coupling a transmitter of a first port to a receiver of a second port;

(2) transmitting a signal from the transmitter of the first port to the receiver of the second port; and

(3) varying the amplitude of the transmitter of the first port over a range of amplitude settings and detecting if the signal transmitted by the transmitter of the first port has been received by the receiver of the second port without error over the range of amplitude settings of the transmitter of the first port.

2. The method of claim 1, wherein step (3) includes the step of detecting if the dynamic range of the receiver of the second port has been exceeded.

3. The method of claim 2, wherein step (3) further includes examining the ADC of the receiver of the second port to detect if the ADC is in an overflow/underflow condition.

4. The method of claim 1, wherein step (3) includes the step of detecting if the receiver of the second port correctly converged to the signal received from the transmitter of the first port.

5. The method of claim 1, wherein step (3) includes the step of detecting if the amplitude of the transmitter of the first port is consistent with the gain of the PGA of the receiver of the second port.

6. The method of claim 1, wherein step (3) is followed by:

(4) repeating step (3) for a range of gain settings of the PGA of the receiver of the second port.

7. The method of claim 6, wherein step (3) includes acquiring metrics of the receiver of the second port, comprising:

(a) acquiring metrics related to the performance of the receiver of the second port; and

(b) comparing the acquired metrics to threshold limits.

8. The method of claim 7, wherein step (a) is preceded with the step of toggling the PGA of the receiver of the second port between its current and previous gain settings.

9. The method of claim 7, wherein step (b) includes acquiring metrics for at least one of a signal to noise ratio (SNR), a bit error, and a PGA monotonicity of the receiver of the second port.

10. The method of claim 1, wherein step (1) includes setting the gain of the PGA of the receiver of the second port to minimum gain and setting the amplitude of the transmitter of the first port to maximum amplitude and step (3) comprises:

(a) decreasing the amplitude of the transmitter of the first port if the dynamic range of the receiver of the second port has been exceeded;

(b) detecting if the receiver of the second port has correctly converged to the signal received from the transmitter of the first port;

(c) detecting if the amplitude of the transmitter of the first port is consistent with the gain of the PGA of the receiver of the second port;

(d) increasing the gain of the PGA of the receiver of the second port; and

(e) repeating steps (a)-(d) while the gain of the PGA of the receiver of the second port is not at a maximum.

11. The method of claim 10, wherein step (e) includes the step of interrupting the repetition of steps (a)-(d) if the amplitude of the transmitter of the first port is inconsistent with the gain of the PGA of the receiver of the second port.

12. A transceiver having a plurality of ports, comprising:

a first port including a transmitter with variable amplitude;

a second port including a receiver having a programmable gain amplifier (PGA) and an analog to digital converter (ADC);

the output of the transmitter of the first port connected to the input of the receiver of the second port;

wherein multiple signals are transmitted from the transmitter of the first port to the receiver of the second port having a range of amplitude settings, the receiver of the second port is monitored to detect if the signals transmitted by the transmitter of the first port has been received by the receiver of the second port without error over the range of amplitude settings of the transmitter of the first port.

13. The transceiver of claim 12, wherein the receiver of the second port is monitored to detect if the dynamic range of the receiver of the second port has been exceeded.

14. The transceiver of claim 13, wherein the ADC of the receiver of the second port is monitored to detect if an underflow or overflow condition has been created over the range of amplitude values.

15. The transceiver of claim 12, wherein the receiver of the second port is monitored to detect if the receiver of the second port correctly converged to the signal received from the transmitter of the first port.

16. The transceiver of claim 12, wherein the PGA of the receiver of the second port and the transmitter of the first port are monitored to detect if the amplitude of the transmitter of the first port is consistent with the gain of the PGA of the receiver of the second port.

17. The transceiver of claim 12, wherein the receiver of the second port is monitored while the amplitude of the transmitter of the first port is varied for a range of gain settings of the PGA of the receiver of the second port.

18. The transceiver of claim 17, wherein metrics related to the performance of the receiver of the second port are acquired and compared to threshold limits.

19. The transceiver of claim 18, wherein the PGA of the receiver of the second port is toggled between its current and previous gain settings prior to the metrics related to the performance of the receiver of the second port are acquired and compared to the threshold limits.

20. The transceiver of claim 18, wherein the metrics acquired includes at least one of a signal to noise ratio (SNR), a bit error, and a PGA monotonicity of the receiver of the second port.

21. The transceiver of claim 12, wherein the amplitude of the transmitter of the first port is set to maximum amplitude, and the gain of the PGA of the receiver of the second port is set to minimum gain, and the amplitude of the transmitter of the first port and the gain of the PGA of the receiver of the second port are varied, wherein:

the receiver of the second port is monitored and the amplitude of the transmitter of the first port is decreased if the dynamic range of the receiver of the second port has been exceeded.

22. The transceiver of claim 12, wherein the amplitude of the transmitter of the first port is set to maximum amplitude, and the gain of the PGA of the receiver of the second port is set to minimum gain, and the amplitude of the transmitter of the first port and the gain of the PGA of the receiver of the second port are varied, wherein:

the receiver of the second port is monitored to detect if the receiver of the second port has correctly converged to the signal received from the transmitter of the first port.

23. The transceiver of claim 12, wherein the amplitude of the transmitter of the first port is set to maximum amplitude, and the gain of the PGA of the receiver of the second port is set to minimum gain, and the amplitude of the transmitter of the first port and the gain of the PGA of the receiver of the second port are varied, wherein:

the transmitter of the first port and the PGA of the receiver of the second port are monitored to detect if the gain of the PGA of the receiver of the second port is consistent with the amplitude of the transmitter of the first port.

24. The transceiver of claim 12, wherein the amplitude of the transmitter of the first port is set to maximum amplitude, and the gain of the PGA of the receiver of the second port is set to minimum gain, and the amplitude of the transmitter of the first port and the gain of the PGA of the receiver of the second port are varied, wherein:

the receiver of the second port is monitored and the amplitude of the transmitter of the first port is decreased if the dynamic range of the receiver of the second port has been exceeded;

the transmitter of the first port and the PGA of the receiver of the second port are monitored to detect if the gain of the PGA of the receiver of the second port is consistent with the amplitude of the transmitter of the first port; and

the gain of the PGA of the receiver of the second port is increased.

25. The transceiver of claim 12, wherein the amplitude of the transmitter of the first port is set to maximum amplitude, and the gain of the PGA of the receiver of the second port is set to minimum gain, and the amplitude of the transmitter of the first port and the gain of the PGA of the receiver of the second port are varied, wherein:

the transmitter of the first port and the PGA of the receiver of the second port are monitored and the varying of the amplitude of the transmitter of the first port and varying of the gain of the PGA of the receiver of the second port are interrupted if the amplitude of the transmitter of the first port is inconsistent with the gain of the PGA of the receiver of the second port.