Receiver, transceiver circuit, signal transmission method, and signal transmission system

• US 7,991,359 B2
• Filed: 09/21/2010
• Issued: 08/02/2011
• Est. Priority Date: 07/14/1999
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Tamura, Hirotaka
• Primary Examiner(s): Trinh; Tan
• Application Number:
  US12/886,942
• Publication Number:
  US 20110012639A1
• Time in Patent Office: 315 Days
• Field of Search: 455/63.1, 455/114.2, 455/139, 455/151.4, 455/245.2, 455/230, 455/250, 455/251.1, 455/256, 455/334, 455/73, 455/226.1, 455/291, 455/296, 713/1, 713/300, 713/401, 341/53, 341/117, 341/118, 341/119, 341/144, 375/219, 375/257, 375/346, 236/22, 333/32, 333/155
• US Class Current: 455/63.1
• CPC Class Codes: H03F 3/45183 Long tailed pairs H03F3/4521, H03F3/45237 take precedence
• CPC Class Codes: H03F 3/45475 using IC blocks as the active amplifying circuit
• CPC Class Codes: H03F 3/45762 using switching means, e.g. sample and hold
• CPC Class Codes: H03F 3/45986 using switching means, e.g. sample and hold
• CPC Class Codes: H04L 25/0274 Arrangements for ensuring balanced coupling
• CPC Class Codes: H04L 25/0292 Arrangements specific to the receiver end
• 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 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/1461 Suppression of signals in the return path, i.e. bidirectional control circuits
• CPC Class Codes: H04L 7/033 using the transitions of the received signal to control the phase of the synchronising-signal-generating means, e.g. using a phase-locked loop

Abstract

A receiver has an offset application circuit for applying a known offset to an input signal, and a decision circuit for comparing the offset-applied input signal with a reference voltage. The level of the input signal is determined based on the known offset and on the result output from the decision circuit. With this configuration, a large common mode voltage can be eliminated in a circuit used for signal transmission.

Claims

1. A transceiver circuit comprising:

a driver for outputting a transmit signal onto a signal transmission line;

a receiver for receiving a receive signal from said signal transmission line; and

a compensation voltage generating circuit for generating a compensation voltage used to compensate for an interference voltage caused by said driver, and for supplying said compensation voltage to said receiver, wherein bidirectional signal transmission is performed by controlling an output level of said compensation voltage generating circuit in accordance with the phase relationship between said transmit signal and said receive signal.

2. The transceiver circuit as claimed in claim 1, wherein said driver is a constant-current driver.

3. The transceiver circuit as claimed in claim 2, wherein said driver includes:

a first driver unit array having a plurality constant-current driver units; and

a second driver unit array having a plurality constant-current driver units, transmit signals being sequentially output by switching between said first and second driver unit arrays.

4. The transceiver circuit as claimed in claim 3, wherein each of said driver unit arrays controls the operating condition of said plurality of constant-current driver units in said each driver unit array and thereby adjusts a transient characteristic of said transmit signal.

5. The transceiver circuit as claimed in claim 4, further comprising:

a predriver for driving each of said driver unit arrays, wherein said predriver is driven by a 4n-phase clock whose cycle is twice as long as bit time T, where n denotes the number of driver units in said each driver unit array.

6. The transceiver circuit as claimed in claim 1, wherein said compensation voltage generating circuit is a replica driver having the same circuit configuration as that of said driver and is driven by the same data as that for said driver, and includes a unit for controlling the output amplitude and transient time of said replica driver.

7. The transceiver circuit as claimed in claim 6, wherein said driver comprises a plurality of driver units, and said replica driver is similar in configuration to one of said driver units constituting said driver.

8. The transceiver circuits as claimed in claim 7, wherein said compensation voltage generating circuit further includes:

a correction circuit for generating, based on a past output bit, a correction signal for improving the accuracy of said compensation voltage at decision timing in said receiver.

9. The transceiver circuit as claimed in claim 1, wherein said compensation voltage generating circuit generates said compensation voltage based on a data sequence consisting of the present bit and past bit of said transmit signal output from said driver and in accordance with the phase relationship between said transmit signal and said receive signal.

10. The transceiver circuit as claimed in claim 9, further comprising:

a unit for determining prior to actual signal transmission a compensation voltage for a boundary across which a decision in said receiver changes from data “

0”

to data “

1”

or from data “

1”

to data “

0”

, by transmitting a test pattern from the driver at one end while setting an output current level at zero in the driver at the other end; and

a unit for storing said determined compensation voltage, and wherein actual signal transmission is performed using said stored compensation voltage.

11. The transceiver circuit as claimed in claim 1, wherein said compensation voltage generating circuit includes:

a plurality of compensation voltage correction circuits each for generating a voltage level that depends on a data sequence consisting of the present bit and past bit of said transmit signal output from said driver and on the phase difference between said transmit signal and said receive signal; and

a selection circuit for selecting the output of one of said plurality of compensation voltage correction circuits in accordance with said data sequence.

12. The transceiver circuit as claimed in claim 11, further comprising:

a unit for determining prior to actual signal transmission a compensation voltage for a boundary across which a decision in said receiver changes from data “

0”

to data “

1”

or from data “

1”

to data “

0”

, by transmitting a test pattern from the driver at one end while setting an output current level at zero in the driver at the other end; and

a unit for storing said determined compensation voltage, and wherein actual signal transmission is performed using said stored compensation voltage.

13. The transceiver circuit as claimed in claim 1, wherein a compensation offset value is determined based on the value of a bit sequence of n past bits including the present bit, and wherein said transceiver circuit includes 2ⁿ receivers corresponding to 2ⁿ kinds of compensation voltages and a selection circuit for selecting a receiver output corresponding to an actual bit sequence.

14. The transceiver circuit as claimed in claim 1, further comprising:

an equalization circuit, provided for said driver or said receiver or for both said driver and said receiver, for compensating for a characteristic of said signal transmission line, and wherein said compensation voltage generating circuit includes a unit for receiving a test pattern and adjusting so as to minimize an interference value from the driver at the same end and intersymbol interference introduced into a signal transmitted from the driver at the opposite end.

15. The transceiver circuit as claimed in claim 1, further comprising:

an impedance holding circuit for holding an output impedance of said driver at a constant value.

16. The transceiver circuit as claimed in claim 1, wherein transient time of the transmit signal output from said driver is set substantially equal to bit time T.

17. A signal transmission system comprising a first transceiver circuit, a second transceiver circuit, and a signal transmission line connecting between said first and second transceiver circuits, wherein at least one of said first and second transceiver circuits is a transceiver circuit comprising:

a driver for outputting a transmit signal onto a signal transmission line;

a receiver for receiving a receive signal from said signal transmission line; and

a compensation voltage generating circuit for generating a compensation voltage used to compensate for an interference voltage caused by said driver, and for supplying said compensation voltage to said receiver, wherein bidirectional signal transmission is performed by controlling an output level of said compensation voltage generating circuit in accordance with the phase relationship between said transmit signal and said receive signal.

18. The signal transmission system as claimed in claim 17, wherein said driver is a constant-current driver.

19. The signal transmission system as claimed in claim 18, wherein said driver includes:

a first driver unit array having a plurality constant-current driver units; and

a second driver unit array having a plurality constant-current driver units, transmit signals being sequentially output by switching between said first and second driver unit arrays.

20. The signal transmission system as claimed in claim 19, wherein each of said driver unit arrays controls the operating condition of said plurality of constant-current driver units in said each driver unit array and thereby adjusts a transient characteristic of said transmit signal.

21. The signal transmission system as claimed in claim 20, wherein said transceiver circuit further comprises:

a predriver for driving each of said driver unit arrays, wherein said predriver is driven by a 4n-phase clock whose cycle is twice as long as bit time T, where n denotes the number of driver units in said each driver unit array.

22. The signal transmission system as claimed in claim 17, wherein said compensation voltage generating circuit is a replica driver having the same circuit configuration as that of said driver and driven by the same data as that for said driver, and includes a unit for controlling the output amplitude and transient time of said replica driver.

23. The signal transmission system as claimed in claim 22, wherein said driver comprises a plurality of driver units, and said replica driver is similar in configuration to one of said driver units constituting said driver.

24. The signal transmission system as claimed in claim 23, wherein said compensation voltage generating circuit further includes:

a correction circuit for generating, based on a past output bit, a correction signal for improving the accuracy of said compensation voltage at decision timing in said receiver.

25. The signal transmission system as claimed in claim 17, wherein said compensation voltage generating circuit generates said compensation voltage based on a data sequence consisting of the present bit and past bit of said transmit signal output from said driver and in accordance with the phase relationship between said transmit signal and said receive signal.

26. The signal transmission system as claimed in claim 25, wherein said transceiver circuit further comprises:

a unit for determining prior to actual signal transmission a compensation voltage for a boundary across which a decision in said receiver changes from data “

0”

to data “

1”

or from data “

1”

to data “

0”

, by transmitting a test pattern from the driver at one end while setting an output current level at zero in the driver at the other end; and

a unit for storing said determined compensation voltage, and wherein actual signal transmission is performed using said stored compensation voltage.

27. The signal transmission system as claimed in claim 17, wherein said compensation voltage generating circuit includes:

a plurality of compensation voltage correction circuits each for generating a voltage level that depends on a data sequence consisting of the present bit and past bit of said transmit signal output from said driver and on the phase difference between said transmit signal and said receive signal; and

a selection circuit for selecting the output of one of said plurality of compensation voltage correction circuits in accordance with said data sequence.

28. The signal transmission system as claimed in claim 27, wherein said transceiver circuit further comprises:

a unit for determining prior to actual signal transmission a compensation voltage for a boundary across which a decision in said receiver changes from data “

0”

to data “

1”

or from data “

1”

to data “

0”

, by transmitting a test pattern from the driver at one end while setting an output current level at zero in the driver at the other end; and

a unit for storing said determined compensation voltage, and wherein actual signal transmission is performed using said stored compensation voltage.

29. The signal transmission system as claimed in claim 17, wherein a compensation offset value is determined based on the value of a bit sequence of n past bits including the present bit, and wherein said transceiver circuit includes 2ⁿ receivers corresponding to 2ⁿ kinds of compensation voltages and a selection circuit for selecting a receiver output corresponding to an actual bit sequence.

30. The signal transmission system as claimed in claim 17, wherein said transceiver circuit further comprises:

an equalization circuit, provided for said driver or said receiver or for both said driver and said receiver, for compensating for a characteristic of said signal transmission line, and wherein said compensation voltage generating circuit includes a unit for receiving a test pattern and making an adjustment so as to minimize an interference value from the driver at the same end and intersymbol interference introduced into a signal transmitted from the driver at the opposite end.

31. The signal transmission system as claimed in claim 17, wherein said transceiver circuit further comprises:

an impedance holding circuit for holding an output impedance of said driver at a constant value.

32. The signal transmission system as claimed in claim 17, wherein transient time of the transmit signal output from said driver is set substantially equal to bit time T.

33. A signal transmission method, having a driver for outputting a transmit signal onto a signal transmission line and a receiver for receiving a receive signal from said signal transmission line, in which a compensation voltage used to compensate for an interference voltage caused by said driver is generated and supplied to said receiver, wherein bidirectional signal transmission is performed by controlling the level of said compensation voltage in accordance with the phase relationship between said transmit signal and said receive signal.

34. The signal transmission method as claimed in claim 33, wherein said compensation voltage is generated based on a data sequence consisting of the present bit and past bit of said transmit signal output from said driver and in accordance with the phase relationship between said transmit signal and said receive signal.

35. The signal transmission method as claimed in claim 34, wherein a compensation voltage for a boundary across which a decision in said receiver changes from data “

0”

to data “

1”

or from data “

1”

to data “

0”

is determined prior to actual signal transmission by transmitting a test pattern from the driver at one end while setting an output current level at zero in the driver at the other end, said determined compensation voltage is stored in memory, and actual signal transmission is performed using said stored compensation voltage.

36. The transmission method as claimed in claim 33, wherein transient time of the transmit signal output from said driver is set substantially equal to bit time T.