Clock and data recovery sampler calibration
First Claim
1. A method of adjusting voltage offset in a receiver, the method comprising:
- in a normal mode, synchronizing to a serial bit stream using one or more data samplers and one or more edge samplers, wherein the data samplers sample the serial bit stream in a data portion to retrieve data, and the edge samplers sample the serial bit stream in a transition portion for synchronization;
in an adjustment mode, using the same one or more data samplers to sample the transition portion to observe a voltage offset at an input of at least one of the one or more data samplers; and
compensating for the voltage offset of the one or more data samplers based at least partly on the observed voltage offsets.
18 Assignments
0 Petitions
Accused Products
Abstract
Methods and apparatus are disclosed, such as those involving clock and data recovery sampler calibration. One such method includes receiving an electronic data stream by a clock and data recovery (CDR) circuit comprising a data sampler and an edge sampler. The data stream includes data portions and transitioning portions. The method further includes conducting calibration of the CDR circuit. The calibration includes acquiring samples from the transitioning portions of the data stream using the data sampler; and calibrating the data sampler based at least partially on the samples acquired using the data sampler. The method allows one not only to improve performance, but also to improve yield and reduce testing and screening requirements without requiring any additional circuitry to detect the offsets and works with regular input signals.
-
Citations
23 Claims
-
1. A method of adjusting voltage offset in a receiver, the method comprising:
-
in a normal mode, synchronizing to a serial bit stream using one or more data samplers and one or more edge samplers, wherein the data samplers sample the serial bit stream in a data portion to retrieve data, and the edge samplers sample the serial bit stream in a transition portion for synchronization; in an adjustment mode, using the same one or more data samplers to sample the transition portion to observe a voltage offset at an input of at least one of the one or more data samplers; and compensating for the voltage offset of the one or more data samplers based at least partly on the observed voltage offsets. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. An apparatus comprising:
-
one or more data samplers coupled to a bit stream, the bit stream having data portions and transition portions; one or more edge samplers coupled to the bit stream; and a clock and data recovery circuit, wherein in a normal mode, the clock and data recovery circuit is configured to provide a data clock signal for the one or more data samplers for sampling of the data portions and to provide an edge clock signal for the one or more edge samplers for sampling of the transition portions, wherein in an adjustment mode, the clock and data recovery circuit is configured to provide the edge clock signal to the one or more data samplers to observe voltage offsets at inputs of the one or more data samplers, the clock and data recovery circuit being further configured to compensate for the voltage offsets based at least partly on the observed voltage offsets. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
-
Specification