Receiver

• US 8,208,592 B2
• Filed: 04/05/2002
• Issued: 06/26/2012
• Est. Priority Date: 04/06/2001
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Vilhonen, Sami
• Primary Examiner(s): Bocure, Tesfaldet
• Application Number:
  US10/117,372
• Publication Number:
  US 20030053569A1
• Time in Patent Office: 3,735 Days
• Field of Search: 455/78, 455/130, 455/230, 455/232.1, 455/232.2, 455/234, 455/239.1, 455/240, 455/323, 455/324, 375/317, 375/345, 375/316, 375/377, 375/318, 375/260, 375/259, 330/250, 330/259, 330/262, 330/270, 330/278
• US Class Current: 375/354
• CPC Class Codes: H03D 3/008 Compensating DC offsets
• CPC Class Codes: H03F 2203/45212 the differential amplifier being designed to have a reduced offset
• CPC Class Codes: H03F 3/45475 using IC blocks as the active amplifying circuit
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22

Abstract

A receiver and a method for a receiver is disclosed. The receiver comprises a signal processing path for receiving a first signal modulated by a first modulation method and having a first bandwidth and a second signal modulated by a second modulation method and having a second bandwidth. A common gain control function is provided for processing said first and second signals. A common DC offset cancellation is also provided for said first and second signals. In a preferred embodiment the gain control and the DC offset cancellation a provided by a single circuit.

Claims

1. An apparatus comprising:

a signal processing path for receiving a first signal modulated by a first modulation method and having a first bandwidth and a second signal modulated by a second modulation method and having a second bandwidth;

a single circuit for providing both DC offset control and gain control for said first and second signals;

wherein the single circuit comprises a first input for the signals and a second input for a reference signal and the output of the common gain control circuit is controlled in response to the reference signal.

2. An apparatus as claimed in claim 1, wherein the single circuit is provided by an inverting amplifier.

3. An apparatus as claimed in claim 2, wherein said inverting amplifier comprises:

an operational amplifier;

a circuit connected on the signal path at a first location before the operational amplifier and a second location after the operational amplifier, said circuit being provided with a resistor; and

a further resistor on the signal path at a location before said first location.

4. An apparatus as claimed in claim 1, wherein the reference signal comprises a reference voltage supplied by a device that receives the signal from the output of the single circuit.

5. An apparatus as claimed in claim 4, wherein the output voltage of the single circuit is adjusted to equal the reference voltage.

6. An apparatus as claimed in claim 1, wherein the signal processing path comprises buffering means.

7. An apparatus as claimed in claim 6, wherein the signal processing path is adapted for a sample/hold type operation.

8. An apparatus as claimed in claim 6, comprising a further circuit for provision of a connection between the output of the single circuit and input of the buffering means.

9. An apparatus as claimed in claim 8, wherein the further circuit is adapted for switching between on and off states.

10. An apparatus as claimed in claim 1, comprising a sensing circuit connected between an input and output of an operational amplifier of the single circuit.

11. An apparatus as claimed in claim 10, wherein the sensing circuit comprises a RC lowpass filter.

12. An apparatus as claimed in claim 1, wherein the modulation of the first signal is based on wideband code division multiple access.

13. An apparatus as claimed in claim 1, wherein the first signal comprises a signal from a transmitter of a third generation communication system.

14. An apparatus as claimed in claim 13, wherein the communication system is based on a universal mobile telecommunications service (UMTS) standard.

15. An apparatus as claimed in claim 1, wherein the modulation of the second signal is based on Gaussian-filtered Minimum Shift Keying.

16. An apparatus as claimed in claim 1, wherein the second signal comprises a signal from a transmitter of a GSM communication system.

17. A method in a receiver comprising:

receiving in a signal processing path of the receiver a first signal modulated by a first modulation method and having a first bandwidth;

receiving in said signal processing path a second signal modulated by a second modulation method and having a second bandwidth;

processing said first signal and said second signal in a single circuit providing common gain control function and a common DC offset cancelling function;

inputting a reference signal into the common gain control function; and

controlling the output of the common gain control function in response to the reference signal.

18. A method as claimed in claim 17, wherein the single circuit comprises an operational amplifier provided with a first and a second input that are kept in a fixed potential.

19. A method as claimed in claim 17, wherein the DC level of the output of the signal processing path is adjusted based on the reference signal.

20. A method as claimed in claim 17, wherein the reference signal comprises a current drawn from a stage that precedes the common DC offset cancelling function.

21. A receiver comprising:

a signal processing path for receiving a first signal modulated by a first modulation method and having a first bandwidth and a second signal modulated by a second modulation method and having a second bandwidth; and

a single circuit for providing a common gain control circuit for said first and second signals and a common DC offset cancelling circuit for said first and second signals, wherein the gain control circuit comprises an operational amplifier provided with a first input for the signals and a second input for a reference signal, a subcircuit connected on the signal path at a first location before the operational amplifier and a second location after the operational amplifier, said subcircuit being provided with a resistor, and a further resistor on the signal path at a location before said first location.

22. A method in a receiver comprising:

receiving in a signal processing path of the receiver a first signal modulated by a first modulation method and having a first bandwidth;

receiving in said signal processing path a second signal modulated by a second modulation method and having a second bandwidth;

processing said first signal and said second signal in a single circuit providing a common gain control function and a common DC offset cancelling function, wherein the gain control function of the single circuit comprises an operational amplifier provided with a first and a second input and the first and second signals are received in the first input of the gain control function;

receiving a reference signal in the second input of the common gain control function; and

maintaining the first input and the second input in a fixed potential by means of a subcircuit, the subcircuit being connected on the signal path at a first location before the operational amplifier and a second location after the operational amplifier and comprising a resistor, and a further resistor on the signal path at a location before said first location.

23. An apparatus comprising:

a signal processing path configured to receive a first signal modulated by a first modulation scheme and a second signal modulated by a second modulation second, wherein the first signal and the second signal are received over a radio communication system; and

a single circuit for providing DC offset control and gain control for the first signal and the second signal,

wherein the single circuit includes a first input for the signals and a second input for a reference signal, and the output of the single circuit is controlled in response to the reference signal.

24. An apparatus as claimed in claim 23, wherein the single circuit is configured to fix a DC level at the output regardless of the DC level at the input.

25. A method comprising:

receiving a first signal modulated by a first modulation scheme and a second signal modulated by a second modulation second, wherein the first signal and the second signal are received over a radio communication system; and

providing DC offset control and gain control, using a single circuit, for the first signal and the second signal,

wherein the single circuit includes a first input for the signals and a second input for a reference signal, and the output of the single circuit is controlled in response to the reference signal.

26. A method as claimed in claim 25, wherein the single circuit is configured to fix a DC level at the output regardless of the DC level at the input.