Multiple high-speed bit stream interface circuit
View Patent ↗A high-speed bit stream interface module interfaces a high-speed communication media to a communication Application Specific Integrated Circuit (ASIC) via a Printed Circuit Board (PCB) or the communication ASIC to another communication ASIC. The high-speed bit stream interface includes a plurality of signal conditioning circuits. The signal conditioning circuits service each of an RX path and a TX path and include a limiting amplifier and a clock and data recovery circuit. The signal conditioning circuit may also include an equalizer and/or an output pre-emphasis circuit. The clock and data recovery circuit has an adjustable Phase Locked Loop (PLL) bandwidth that is set to correspond to a jitter bandwidth of a serviced high-speed bit stream.
1. A high-speed serial bit stream interface module comprises:
at least one multiplexer that multiplexes a plurality of transmit bit streams to produce a line side transmit signal;
at least one demultiplexer that demultiplexes a line side receive signal to produce a plurality of receive bit streams;
a plurality of signal conditioning circuits, each of which services a respective bit stream of the plurality of transmit bit streams and the plurality of receive bit streams to address characteristics of each of the transmit and the receive bit streams and corresponding paths based upon a control input; and
a control circuit configured to generate and produce the control input based upon the characteristics of each of the transmit and the receive bit streams and corresponding paths.
2. The high-speed serial bit stream interface module of claim 1 , wherein each of the plurality of signal conditioning circuits spectrally shapes its serviced bit stream.
3. The high-speed serial bit stream interface module of claim 2 , wherein the plurality of signal conditioning circuits spectrally shape their respective bit streams to remove deterministic jitter.
4. The high-speed serial bit stream interface module of claim 2 , wherein the plurality of signal conditioning circuits spectrally shape their respective bit streams to remove inter symbol interference.
5. The high-speed serial bit stream interface module of claim 1 , wherein each of the plurality of signal conditioning circuits comprise:
a limiting amplifier that receives a serviced signal and that amplifies the serviced signal to produce the serviced signal in a desired output range;
a clock and data recovery circuit having an adjustable Phase Locked Loop (PLL) bandwidth that communicatively couples to the output of the limiting amplifier and that receives, recovers, and reclocks the serviced signal; and
wherein the PLL bandwidth of the clock and data recovery circuit is controllable to correspond to the signal characteristics of the serviced signal.
6. The high-speed serial bit stream interface module of claim 5 , wherein:
the PLL bandwidth of signal conditioning circuits servicing transmit signals is based upon output characteristics of a device producing the transmit signals to the board side interface; and
the PLL bandwidth of signal conditioning circuits servicing receive signals is based upon output characteristics of a device producing the receive signals to the line side interface.
7. The high-speed serial bit stream interface module of claim 5 , wherein the signal conditioning circuits each further comprise:
an output pre-emphasis circuit communicatively coupled to the output of the clock and data recovery circuit that controllably modifies the spectrum of the serviced signal to pre-compensate for spectral characteristics of a signal path upon which the serviced signal will be output.
8. The high-speed serial bit stream interface module of claim 5 , wherein the signal conditioning circuits each further comprise:
an equalizer communicatively coupled to the output of the limiting amplifier that controllably spectrally shapes the serviced signal to compensate for spectral characteristics of a signal path from which the serviced signal was received.
9. The high-speed serial bit stream interface module of claim 5 , wherein the signal conditioning circuits each further comprise:
a limiting amplifier that receives the serviced signal and that controllably amplifies the serviced signal to produce the serviced signal in a desired output range.
10. The high-speed serial bit stream interface module of claim 1 , further comprising:
a receive lane synchronizer that services the plurality of receive bit streams; and
a transmit lane synchronizer that services the plurality of transmit bit streams.
11. The high-speed serial bit stream interface module of claim 10 , wherein:
the receive lane synchronizer operates by inserting at least one bit pattern into the plurality of receive bit streams; and
the transmit lane synchronizer operates by inspecting at least one bit pattern contained in the plurality of transmit bit streams and realigning the plurality of transmit bit streams when required as determined by the inspection.
12. The high-speed serial bit stream interface module of claim 1 further comprises:
a receive Forward Error Correction (FEC) block that services the plurality of receive bit streams; and
a transmit FEC block that services the plurality of transmit bit streams.
13. A method of operating a high-speed serial bit stream interface module comprises:
multiplexing with at least one multiplexer a plurality of transmit bit streams to produce a line side transmit signal;
demultiplexing with at least one demultiplexer a line side receive signal to produce a plurality of receive bit streams; and
servicing a bit stream of the plurality of transmit bit streams and the plurality of receive bit streams with a respective signal conditioning circuit of a plurality of signal conditioning circuits to address characteristics of each of the transmit and the receive bit streams and corresponding paths, the servicing of the bit stream being based upon a control input, wherein the servicing of the bit stream includes generating and producing the control input, via a control circuitry, based upon the characteristics of each of the transmit and the receive bit streams and corresponding paths.
14. The method of claim 13 , wherein the servicing the bit stream includes spectrally shaping the serviced bit stream.
15. The method of claim 14 , wherein the spectrally shaping the serviced bit stream operates to remove deterministic jitter.
16. The method of claim 14 , wherein the spectrally shaping the serviced bit stream operates to remove inter symbol interference.
17. The method of claim 14 , wherein the servicing the bit stream further comprises:
modifying the spectrum of the serviced bit stream to pre-compensate for spectral characteristics of a signal path upon which the serviced bit stream will be output.
18. The method of claim 13 further comprises:
servicing the receive bit streams with a receive lane synchronizer, which operates by inserting at least one bit pattern into the first plurality of transmit bit streams; and
servicing the transmit bit stream with a transmit lane synchronizer, which operates by inspecting at least one bit pattern contained in the first plurality of transmit bit streams and realigning the first plurality of transmit bit streams when required as determined by the inspection.
19. A method of operating a high-speed serial bit stream interface module comprises:
multiplexing a plurality of transmit bit streams to produce a line side transmit signal;
demultiplexing a line side receive signal to produce a plurality of receive bit streams; and
servicing a bit stream of the plurality of transmit bit streams and of the plurality of receive bit streams with a respective signal conditioning circuit of a plurality of signal conditioning circuits to address characteristics of each of the transmit and of the receive bit stream and corresponding paths based upon a control input, wherein the control input is generated, via a control circuit, based upon the characteristics of each of the transmit and of the receive bit streams and corresponding paths.
20. The method of claim 19 , wherein servicing the bit stream includes spectrally shaping the serviced bit stream.