A physical layer device includes a cable tester that determines a cable status of a cable and that includes a test module. The test module transmits a test pulse on the cable, measures a reflection amplitude, calculates a cable length, and determines the cable status based on the measured amplitude and the calculated cable length. An insertion loss estimator communicates with the cable tester, and estimates insertion loss of the cable based at least in part on a feedback equalizer gain.
1. A physical layer device, comprising:
a cable tester that determines a cable status of a cable and that includes a test module, wherein said test module:
transmits a test pulse on the cable,
measures a reflection amplitude,
calculates a cable length, and
determines said cable status based on said measured reflection amplitude and said calculated cable length; and
an insertion loss estimator that communicates with said cable tester and that estimates insertion loss of the cable based at least in part on a feedback equalizer gain.
2. The physical layer device of claim 1 wherein said cable status includes an open status, a short status, and a normal status.
3. The physical layer device of claim 1 further comprising a digital signal processor (DSP) that communicates with said insertion loss estimator and that includes a plurality of gain parameters, wherein said insertion loss estimator estimates said insertion loss based on said gain parameters of said DSP.
4. The physical layer device of claim 3 further comprising a cable length estimator that estimates cable length based on at least one of said plurality of gain parameters.
5. The physical layer device of claim 3 wherein said gain parameters include at least one of a partial transmitter response, an analog low pass filter gain, an analog gain, a digital gain, a feed forward equalizer gain, and the feedback equalizer gain.
6. The physical layer device of claim 5 wherein said insertion loss is calculated based upon:
H
(
D
)
=
1
+
FB
(
D
)
T
(
D
)
LPF
(
D
)
G
A
G
D
FF
(
D
)
wherein FB(D) is said feedback equalizer gain, T(D) is said partial transmitter response, LPF(D) is said analog low pass filter gain, G A is said analog gain, G D is said digital gain, and FF(D) is said feed forward equalizer gain.
7. The physical layer device of claim 1 wherein said test module:
compares said estimated insertion loss to at least one of a predetermined threshold and a lookup table; and
determines an insertion loss pass/fail status based on said comparison.
8. The physical layer device of claim 7 further comprising an indicator for displaying at least one of said cable status, said insertion loss test pass/fail status, said estimated insertion loss, said calculated cable length and said measured reflection amplitude.
9. The physical layer device of claim 1 wherein said physical layer device is implemented in a network device.
10. The physical layer device of claim 1 wherein said cable tester is integrated with said physical layer device in a single integrated circuit.
11. The physical layer device of claim 1 wherein said physical layer device is implemented in an Ethernet device that is 802.3ab compliant.
12. A physical layer device, comprising:
a cable tester that determines a cable status of a cable and that includes a test module, wherein said test module:
transmits a test pulse on the cable,
measures a reflection amplitude,
calculates a cable length, and
determines said cable status based on said measured reflection amplitude and said calculated cable length;
a return loss estimator that communicates with said cable tester and that estimates return loss of the cable based on gain parameters of said physical layer device, wherein said gain parameters include at least an echo canceller response; and
a digital signal processor (DSP) that communicates with said return loss estimator and that has a plurality of gain parameters, wherein said return loss estimator estimates said return loss based on said gain parameters of said DSP
wherein said gain parameters include at least one of a partial transmitter response, an analog low pass filter gain, an analog gain, and said echo canceller response, and
wherein said return loss estimate is calculated based upon:
R
(
D
)
=
Echo
(
D
)
T
(
D
)
LPF
(
D
)
G
A
wherein T(D) is said partial transmitter response, LPF(D) is said analog low pass filter gain, G A is said analog gain, and Echo(D) is said echo canceller response.
13. The physical layer device of claim 12 wherein said cable status includes an open status, a short status, and a normal status.
14. The physical layer device of claim 12 further comprising a cable length estimator that estimates cable length based on at least one of said plurality of gain parameters.
15. The physical layer device of claim 12 wherein said cable test module:
compares said return loss estimate to at least one of a predetermined threshold and a lookup table; and
determines a return loss pass/fail status based on said comparison.
16. The physical layer device of claim 15 further comprising an indicator for displaying at least one of said cable status, said return loss pass/fail status, said estimated return loss, said calculated cable length and said measured reflection amplitude.
17. The physical layer device of claim 12 wherein said physical layer device is implemented in a network device.
18. The physical layer device of claim 12 wherein said cable tester is integrated with a physical layer device in a single integrated circuit.