Receiver

• US 20030053569A1
• Filed: 04/05/2002
• Published: 03/20/2003
• Est. Priority Date: 04/06/2001
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Vilhonen, Sami
• Granted Patent: US 8,208,592 B2
• Time in Patent Office: Days
• US Class Current: 375/345
• 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. 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;

a common gain control circuit for said first and second signals; and

a common DC offset cancelling circuit for said first and second signals.

2. A receiver as claimed in claim 1, wherein said common gain control and said common DC offset cancelling are provided by a single circuit.

3. A receiver as claimed in claim 1, wherein the gain control circuit comprises a first input for the signals and a second input for a reference signal.

4. A receiver as claimed in claim 1, wherein the gain control circuit is provided by an inverting amplifier.

5. A receiver as claimed in claim 4, 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 location before said first location.

6. A receiver as claimed in claim 1, wherein the output of the gain control circuit is controlled in response to a reference signal.

7. A receiver as claimed in claim 6, wherein the reference signal comprises a reference voltage supplied by a device that receives signal from the output of the gain control circuit.

8. A receiver as claimed in claim 7, wherein the output voltage of the gain control circuit is adjusted to equal with the reference voltage.

9. A receiver as claimed in claim 1, wherein the signal processing path comprises buffering means.

10. A receiver as claimed in claim 9, wherein the signal processing path is adapted for sample/hold type operation.

11. A receiver as claimed in claim 9, comprising a further circuit for provision of a connection between the output of the common gain control circuit and input of the buffering means.

12. A receiver as claimed in claim 11, wherein the further circuit is adapted for switching between on and off states.

13. A receiver as claimed in claim 1, comprising a sensing circuit connected between an input and output of a operational amplifier of the DC cancelling circuit.

14. A receiver as claimed in claim 13, wherein the sensing circuit comprises a RC lowpass filter.

15. A receiver as claimed in claim 1, wherein the modulation of the first signal is based on wideband code division multiple access.

16. A receiver as claimed in claim 1, wherein the first signal comprises a signal from a transmitter of a third generation communication system.

17. A receiver as claimed in claim 16, wherein the communication system is based on a universal mobile telecommunications service (UMTS) standard.

18. A receiver as claimed in claim 1, wherein the modulation of the second signal is based on Gaussian-filtered Minimum Shift Keying.

19. A receiver as claimed in claim 1, wherein the second signal comprises a signal from a transmitter of a GSM communication system.

20. 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; and

processing said first signal and said second signal by a common gain control function and a common DC offset cancelling function.

21. A method as claimed in claim 20, wherein the gain control function and the DC offset cancelling function are provided by means of a common circuit.

22. A method as claimed in claim 20, wherein the gain control circuit comprises an operational amplifier provided with a first and a second input that are kept in a fixed potential.

23. A method as claimed in claim 20, wherein the DC level of the output of the signal processing path is adjusted based on a reference signal.

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