Reciprocal quantum logic (RQL) serial data receiver system

Patent metadata

Field	Value
Publication number	US-10083148-B2
Application number	US-201615217003-A
Country	US
Kind code	B2
Filing date	Jul 22, 2016
Priority date	Jul 22, 2016
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

One embodiment describes a reciprocal quantum logic (RQL) receiver system. The RQL system is configured to convert a serial input data stream provided from a serial data transmitter into an RQL data stream. The RQL receiver system includes a sampling controller configured to oversample the serial input data stream via a plurality of samples over each sampling window of an RQL clock signal to determine a transition sample corresponding to a transition in a digital value of the serial input data stream in a given one sampling window of the RQL clock signal. The RQL receiver system can be further configured to capture the digital value of the serial input data stream via a capture sample that is a predetermined number of samples subsequent to the transition sample in each sampling window of the RQL clock signal.

First claim

What is claimed is:

1. A reciprocal quantum logic (RQL) receiver system configured to convert a serial input data stream provided from a serial data transmitter into an RQL data stream, the RQL receiver system comprising:
a sampling controller configured to oversample the serial input data stream via a plurality of samples over each of a plurality of sampling windows of an RQL clock signal to determine a transition sample corresponding to one of the plurality of samples associated with a transition in a digital value of the serial input data stream in a given one sampling window of the RQL clock signal,
the RQL receiver system being further configured to capture the digital value of the serial input data stream via a capture sample that is a predetermined number of samples subsequent to a location of the transition sample in each sampling window of the RQL clock signal.

2. The system of claim 1 , wherein the RQL clock signal is a quadrature clock signal comprising an in-phase component and a quadrature-phase component and having a frequency that is approximately equal to twice a frequency of the serial input data stream, such that the sampling controller is configured to sample the serial input data stream at each positive and negative peak of the RQL clock signal to provide eight samples of the serial input data stream over each sampling window of the RQL clock signal.

3. The system of claim 1 , wherein the sampling controller is configured to capture the digital value of the serial input data stream via the capture sample that is a number of samples equal to half of the plurality of samples corresponding to each sampling window of the RQL clock signal subsequent to the location of the transition sample in each sampling window of the RQL clock signal.

4. The system of claim 3 , wherein the capture sample is a first capture sample, wherein the sampling controller is further configured to capture the digital value of the serial input data stream via at least one additional capture sample that corresponds to a respective at least one next or at least one previous sample with respect to the first capture sample, wherein the sampling controller is further configured to determine the digital value of the serial input data stream in a given sampling window based on a voting algorithm corresponding to the digital value of a majority of captured values of the serial input stream at each of the respective first capture sample and the respective at least one additional capture sample.

5. The system of claim 1 , wherein the sampling controller is configured to monitor the location of the transition sample corresponding to the location of the transition of the digital value of the serial input data stream in each sampling window of the RQL clock signal in which the transition of the digital value of the serial input data stream occurs, and is configured to change a location of the capture sample in each sampling window of the RQL clock signal in response to a change in the location of the transition sample relative to the plurality of samples.

6. The system of claim 1 , wherein the sampling controller comprises an integrator system configured to determine clock drift of the RQL clock signal relative to a clock associated with the serial data transmitter and to filter noise and jitter associated with changes in the transition of the digital value based on changes in the location of the transition sample relative to the plurality of samples.

7. The system of claim 6 , wherein the integrator system comprises at least one counter configured to count a net change in the transition sample with respect to the plurality of samples over a predetermined time and is configured to adjust the location of the capture sample forward or backward relative to the plurality of samples of the sampling window of the RQL clock signal in response to a non-zero net change of the transition sample with respect to the plurality of samples throughout a duration of the predetermined time.

8. The system of claim 7 , wherein the at least one counter comprises:
an advance counter configured to increment an advance count value in response to the location of the transition sample drifting forward relative to the plurality of samples in the RQL clock signal; and
a delay counter configured to increment a delay count value in response to the location of the transition sample drifting backward relative to the plurality of samples in the RQL clock signal, wherein the advance counter is configured to decrement the advance count value in response to the delay counter incrementing the delay count value, and wherein the delay counter is configured to decrement the delay count value in response to the advance counter incrementing the advance count value.

9. The system of claim 1 , wherein the sampling controller is configured to monitor changes in the location of the transition sample corresponding to changes in the transition of the digital value of the serial input data stream relative to the plurality of samples in each sampling window of the RQL clock signal at which the transition occurred via a plurality of counters and to filter the noise and jitter associated with changes in the transition of the digital value based on changes in the transition sample with respect to the plurality of samples via an integrator system.

10. A method for capturing data from a serial input data stream, the method comprising:
receiving the serial input data stream at an input of a reciprocal quantum logic (RQL) receiver system from a serial data transmitter at a first frequency;
sampling the serial input data stream via an RQL clock signal having a second frequency that is twice the first frequency to generate a plurality of samples;
detecting a transition of a digital value of the serial input data stream at a transition sample of the plurality of samples in a given sampling window of the RQL clock signal; and
capturing the digital value of the serial input data stream via a capture sample of the plurality of samples in each sampling window of the RQL clock signal, the capture sample being a predetermined number of samples subsequent to a location of the transition sample in each sampling window of the RQL clock signal.

11. The method of claim 10 , wherein sampling the serial input data stream comprises sampling the serial input data stream at each positive and negative peak of each of an in-phase component and a quadrature-phase component of the RQL clock signal.

12. The method of claim 10 , wherein capturing the digital value comprises capturing the digital value of the serial input data stream via the capture sample that is half of the plurality of samples of each sampling window of the RQL clock signal subsequent to the transition sample in each sampling window of the RQL clock signal.

13. The method of claim 10 , further comprising:
monitoring the location of the transition sample relative to the plurality of samples over a plurality of consecutive sampling windows of the RQL clock signal; and
changing a location of the capture sample relative to the plurality of samples in response to the location of the transition sample having changed from a first location to a second location in each of the plurality of consecutive sampling windows of the RQL clock signal.

14. The method of claim 10 , further comprising:
incrementing an advance counter and decrementing a delay counter in response to the location of the transition sample advancing relative to the plurality of samples in each sampling window of the RQL clock signal;
decrementing the advance counter and incrementing the delay counter in response to the

Assignees

• Shauck Steven Brian
• Northrop Grumman Systems Corp

Inventors

• Shauck Steven Brian

Classifications

• H03K19/00323 Primary

  Delay compensation · CPC title

• G06F13/4286 Primary

  using a handshaking protocol, e.g. RS232C link · CPC title

• H03K19/195

  using superconductive devices · CPC title

• G01R19/2509

  Details concerning sampling, digitizing or waveform capturing · CPC title

• H03K3/38

  by the use, as active elements, of superconductive devices · CPC title