Digital signal receiver with Q-monitor

• US 7,835,464 B2
• Filed: 08/14/2007
• Issued: 11/16/2010
• Est. Priority Date: 08/25/2006
• Status: Expired due to Fees

• Current Assignee: RPX Corporation
• Original Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Inventors: Preisach, Helmut
• Primary Examiner(s): Corrielus, Jean B
• Application Number:
  US11/838,658
• Publication Number:
  US 20080292026A1
• Time in Patent Office: 1,190 Days
• Field of Search: 375/316, 375/226, 375/355, 375/362, 375/371, 341/100, 370/536, 370/542, 370/357, 370359-360, 370/362, 370/366
• US Class Current: 375/316
• CPC Class Codes: H04L 25/061 providing hard decisions only; arrangements for tracking or suppressing unwanted low frequency components, e.g. removal of dc offset removal of dc offset in coupling arrangements H04L25/029, H04L25/0296
• CPC Class Codes: H04L 7/0054 Detection of the synchronisation error by features other than the received signal transition by means of signal transition H04L7/033

Abstract

A digital signal receiver for a high-bitrate digital signal has a serial signal input (20, 20′) and a number of N parallel digital signal outputs (26) with N>1. The receiver contains at least N+1 digital sampling channels (31-35), a Q-monitor (37, 38) for comparing the output signal of at least two of the sampling channels (31-35), and a switch fabric (36) for controllably connecting N of the sampling channels (31-35) to the outputs (26) and at least two of the sampling channels (31-35) to the Q-monitor (37, 38). This allows to use N of the sampling channels to provide the N output signals while at the same time, the at least one remaining sampling channel can be used by the Q-monitor to scan an eye diagram.

Claims

1. A digital signal receiver for a high bit rate digital signal comprising

a serial signal input and

a number of N parallel digital signal outputs with N>

1,

at least N+1 digital sampling channels,

a Q-monitor circuit for comparing the output signal of at least two of said sampling channels, and

a switch fabric for controllably connecting N of said sampling channels to said outputs and at least two of said sampling channels to said Q-monitor.

2. A signal receiver according to claim 1, wherein the Q-monitor comprises an EXOR gate and an error counter.

3. A signal receiver according to claim 1, comprising D flip-flops connected between the switch fabric and the outputs.

4. A signal receiver according to claim 1, further comprising a microcontroller for configuring said switch fabric, for reading out pseudo error count values of said Q-monitor and for determining at least one optimized parameter for at least one of said sampling channels connected via said switch fabric to said Q-monitor.

5. A signal receiver according to claim 4, further comprising a variable gain amplifier and/or an electrical equalizer, wherein the microcontroller is adapted to adjust at least one operational parameter of said variable gain amplifier and/or electrical equalizer in dependence on pseudo error count values delivered by said Q-monitor.

6. A signal receiver according to claim 1, wherein said sampling channels are all of equal design, each comprising a sampler responsive to said serial signal input to provide a sample for comparison with a threshold, a threshold/offset compensation for adjusting the threshold, and a phase shifter to provide a phase shifted clock signal for the comparison.

7. A signal receiver according to claim 1, further comprising a clock recovery circuit for generating a recovered clock signal from said input signal.

8. A signal receiver according to claim 7, wherein said recovered clock signal has a clock rate of 1/N of the bit rate of said input signal.

9. A signal receiver according to claim 7, comprising a microcontroller adapted to adjust phase shifters in said N sampling channels connected via said switch fabric to said outputs leads such that these have phase values mutually shifted by 2.pi./N.

10. A signal receiver according to claim 9, wherein said phase shifters receive from said clock recovery circuit at least two copies of said clock signal, mutually shifted by 90 degrees, wherein said phase shifters are adapted to create a phase shifted clock signal as a weighted sum of said at least two copies of said clock signal and wherein said microcontroller is adapted to adjust the phase shifters by adjusting their weighting factors.

11. A method of regenerating a high bit rate digital signal and converting the high bit rate signal to an N-bit wide parallel output signal with N>

1, comprising the steps of

providing at least N+1 sampling channels;

connecting N of said sampling channels to a parallel signal output, with at least one sampling channel remaining not connected to a parallel signal output;

connecting two of said sampling channels, including the at least one remaining channel, to a Q-monitor;

using said Q-monitor to measure a one- or two-dimensional eye diagram of the at least one remaining sampling channel by varying a phase and/or threshold value thereof; and

repeating said steps using different connections of sampling channels until eye-diagrams for all sampling channels have been measured.