Method of compensating skew, digital communication system, receiver, electronic device, circuit and computer program product
View Patent ↗There is provided a receiver comprising: a control unit for controlling the functions of the receiver; a receiving unit for receiving data signals and timing signals; and a digitally controlled delay line unit connected to the receiving unit and to the control unit. The control unit is configured to measure several samples of the received data signal and the timing signal, to determine average values of the several measured samples of the data signal and the timing signal for defining compensation values, and the digitally controlled delay line unit is configured to adjust the number of unit delay elements for compensating for skew between the data signal and the timing signal on the basis of the defined compensation values.
1. A method comprising:
receiving a data signal and a timing signal by a receiver;
measuring a pulse shape of an eXclusive OR (XOR) signal on the basis of several measured samples of an XOR function of the received data signal and the timing signal;
determining, based on average values of the measured pulse shape of the XOR signal, whether the XOR signal is at a high state or at a low state for a predetermined minimum period of time, wherein the minimum period of time is based on delay differences between the data and timing signals, and further based on at least one of setup-times and hold-times of the receiver; and
adjusting a number of unit delay elements for compensating for skew between the data signal and the timing signal on the basis of whether the XOR signal is at the high state or the low state for the predetermined minimum period of time.
2. The method of claim 1 , the method further comprising adjusting the number of unit delay elements on the basis of whether high state or low state measurements of the XOR signal are used, and on whether the measurement is for a hold-time case or for a setup-time case.
3. The method of claim 1 , wherein measuring the pulse shape of the XOR signal comprises defining a first edge of a pulse of the XOR signal on the basis of the data signal and defining a second edge of the pulse of the XOR signal on the basis of the timing signal.
4. The method of claim 1 , wherein the compensation values are defined by measuring setup-time margins and hold-time margins of the data and the timing signals, and by determining a setup-time margin histogram and a hold-time margin histogram on the basis of the measured setup-time and hold-time margins; and adjusting the number of unit delay elements for compensating for skew between the data and timing signals is based on the shapes of the determined setup-time margin and hold-time margin histograms.
5. The method of claim 1 , wherein the timing signal comprises at least one of a clock signal and a strobe signal.
6. The method of claim 1 , wherein measuring the pulse shape of the XOR signal comprises measuring the several samples of the XOR function via a series of flip-flops.
7. A receiver, comprising:
a control unit configured to control the functions of the receiver;
a receiving unit configured to receive data signals and timing signals;
a digitally controlled delay line unit connected to the receiving unit and to the control unit, the control unit being configured to measure a pulse shape of an eXclusive OR (XOR) signal on the basis of several measured samples of an XOR function of the received data signal and the timing signal, and to determine, based on average values of the measured pulse shape of the XOR signal, whether the XOR signal is at a high state or at a low state for a predetermined minimum period of time, wherein the minimum period of time is based on delay differences between the data and timing signals, and further based on at least one of setup-times and hold-times of the receiver, and the digitally controlled delay line unit being configured to adjust a number of unit delay elements for compensating for skew between the data signal and the timing signal on the basis of whether the XOR signal is at the high state or the low state for the predetermined minimum period of time.
8. The receiver of claim 7 , wherein the control unit comprises a measuring unit configured to measure several samples of the XOR function, and a filtering unit configured to determine average values of the measured pulse shape of the XOR signal for defining the compensation values.
9. The receiver of claim 7 , wherein the control unit further comprises a logic unit configured to determine which measurements of the samples of the XOR function are valid.
10. The receiver of claim 9 , wherein the logic unit is further configured to indicate whether the measurement is for a hold-time case or for a setup-time case.
11. The receiver of claim 7 , wherein the control unit is further configured to define the compensation values by measuring setup-time margins and hold-time margins of the data and the timing signals, and by determining a setup-time margin histogram and a hold-time margin histogram on the basis of the measured setup-time and hold-time margins; and to adjust the number of unit delay elements for compensating for skew between the data and timing signals on the basis of the shapes of the determined setup-time margin and hold-time margin histograms.
12. The receiver of claim 7 , wherein the control unit comprises a series of flip-flops configured to measure the pulse shape of the XOR signal.
13. An apparatus, comprising:
a receiver including:
a receiving unit configured to receive data signals and timing signals;
a control unit configured to measure a pulse shape of an XOR signal on the basis of several measured samples of an eXclusive OR (XOR) function of the received data and timing signals, and determine average values of the measured pulse shape of the XOR signal for defining compensation values;
a digitally controlled delay line unit connected to the receiving unit and to the control unit and configured to adjust a number of unit delay elements for compensating for skew between the data signal and the timing signal on the basis of the defined compensation values; and
a filter unit configured to define the compensation values by measuring setup-time margins and hold-time margins of the data and the timing signals, and by determining a setup-time margin histogram and a hold-time margin histogram on the basis of the measured setup-time and hold-time margins; and wherein the digitally controlled delay line unit is configured to adjust the number of unit delay elements for compensating for skew between the data and timing signals on the basis of the shapes of the determined setup-time margin and hold-time margin histograms.
14. The apparatus of claim 13 , wherein the control unit comprises a series of flip-flops configured to measure the pulse shape of the XOR signal.
15. A circuit for use in a receiver, comprising:
a control block configured to control the functions of the circuit;
a digitally controlled delay line block connected to the control block;
a measuring block configured to measure a pulse shape of an eXclusive OR (XOR) signal on the basis of several measured samples of an XOR function of received data and timing signals;
a filtering block connected to the measuring block and to the control block, and configured to determine, based on average values of the measured pulse shape of the XOR signal, whether the XOR signal is at a high state or at a low state for a predetermined minimum period of time, wherein the minimum period of time is based on delay differences between the data and timing signals, and further based on at least one of setup-times and hold-times of the receiver, and
the digitally controlled delay line block being configured to adjust a number of unit delay elements for compensating for skew between the data signal and the timing signal on the basis of whether the XOR signal is at the high state or the low state for the predetermined minimum period of time.
16. The circuit of claim 15 , further comprising a logic block connected to the delay line block and to the filtering block configured to determine which measurements of the samples of the received data signal and timing signal are valid.
17. The circuit of claim 16 , wherein the logic block is further configured to indicate to the filtering block whether the measurement is for a hold-time case or for a setup-time case.
18. The circuit of claim 15 , wherein the filtering block is further configured to define the compensation values by measuring setup-time margins and hold-time margins of the data and the timing signals, and by determining a setup-time margin histogram and a hold-time margin histogram on the basis of the measured setup-time and hold-time margins, and the delay line block is configured to adjust the number of unit delay elements for compensating for skew between the data and timing signals on the basis of the shapes of the determined setup-time margin and hold-time margin histograms.
19. The circuit of claim 15 , wherein the measuring block comprises a series of flip-flops configured to measure the pulse shape of the XOR signal.
20. An apparatus comprising:
a digital signal processor; and
a computer program product encoding a computer program of instructions for executing a computer process via the apparatus, the process comprising:
receiving a data signal and a timing signal by a receiver;
measuring a pulse shape of an eXclusive OR (XOR) signal on the basis of several measured samples of an XOR function of the received data signal and the timing signal;
determining, based on average values of the measured pulse shape of the XOR signal, whether the XOR signal is at a high state or at a low state for a predetermined minimum period of time, wherein the minimum period of time is based on delay differences between the data and timing signals, and further based on at least one of setup-times and hold-times of the receiver; and
adjusting a number of unit delay elements for compensating for skew between the data signal and the timing signal on the basis of whether the XOR signal is at the high state or the low state for the predetermined minimum period of time.
21. The apparatus of claim 20 , the process further comprising: defining the compensation values by measuring setup-time margins and hold-time margins of the data and the timing signals, and by determining a setup-time margin histogram and a hold-time margin histogram on the basis of the measured setup-time and hold-time margins; and adjusting the number of unit delay elements for compensating for skew between the data and timing signals on the basis of the shapes of the determined setup-time margin and hold-time margin histograms.