Adaptive receiver system that adjusts to the level of interfering signals

• US 6,980,786 B1
• Filed: 01/16/2002
• Issued: 12/27/2005
• Est. Priority Date: 01/16/2001
• Status: Expired due to Term

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: Sequoia Communications Corporation
• Inventors: Groe, John B.
• Primary Examiner(s): LE, LANA N
• Application Number:
  US10/051,761
• Time in Patent Office: 1,441 Days
• Field of Search: 455/232.1, 455/234.1, 455/226.1, 455/226.2, 455/245.1, 455/313, 455/318, 455/338, 455/334, 455/255, 455/258, 455/263, 455/260, 455/261, 455/314, 455/323, 455/63.1, 455/295, 455/234.2, 455/67.13, 455/296, 375/345, 375/327
• US Class Current: 455/314
• CPC Class Codes: H04B 1/109 by improving strong signal performance of the receiver when strong unwanted signals are present at the receiver input
• CPC Class Codes: H04B 1/26 for superheterodyne receivers multiple frequency-changing H03D7/16

Abstract

Adaptive receiver system that adjusts to the level of interfering signals. An adaptive system is provided for use with a radio receiver to adapt to interfering signals associated with a received RF signal. The radio receiver includes a LNA to receive the RF signal and produce an amplified signal that is coupled to a down-converting mixer that produces a mixer output. A peak detector is coupled to receive the mixer output to produce a peak signal. An integrator is coupled to the peak detector to receive the peak signal and produce an integrated signal and a mixer is coupled to receive the integrated signal and a transmit power indicator to produce a current control signal that is coupled to the LNA. The current control signal is used to control a bias current of the LNA, so that cross modulation associated with the received RF signal is reduced.

Claims

1. A radio receiver having an LNA to receive an RF signal and produce an amplified signal that is coupled to a down-converting mixer that produces a mixer output, and the radio receiver comprises:

a peak detector coupled to receive the mixer output to produce a peak signal;

an integrator coupled to the peak detector to receive the peak signal and produce an integrated signal;

a second mixer coupled to receive the integrated signal and a transmit power indicator to produce a current control signal that is coupled to the LNA to control a bias current of the LNA, wherein cross modulation associated with the received RF signal is reduced.

2. A radio receiver having an LNA to receive an RF signal and produce an amplified signal that is coupled to a down-converting mixer that produces a mixer output, and the radio receiver comprises:

a peak detector coupled to receive the mixer output to produce a peak signal;

an integrator coupled to the peak detector to receive the peak signal and produce an integrated signal;

a second third mixer coupled to an output of the integrator and a receiver gain control signal to produce a VCO current control signal that is coupled to a VCO associated with a PLL that drives the down-converting mixer, wherein the reciprocal mixing associated with the received RF signal is reduced by adjustment of the VCO associated with the PLL.

3. An adaptive system for use with a radio receiver to adapt to interfering signals associated with a received RF signal, the radio receiver includes an LNA to receive the RF signal and produce an amplified signal that is coupled to a down-converting mixer that produces a mixer output, the adaptive system comprises:

a peak detector coupled to receive the mixer output to produce a peak signal;

an integrator coupled to the peak detector to receive the peak signal and produce an integrated signal; and

a second mixer coupled to receive the integrated signal and a transmit power indicator to produce a current control signal that is coupled to the LNA to control a bias current of the LNA, wherein cross modulation associated with the received RF signal is reduced.

4. The adaptive system of claim 3, further comprising a filter coupled to receive the mixer output of the downconverting mixer and produce a filtered output that is coupled to the peak detector.

5. The adaptive system of claim 3, further comprising an LNA control circuit coupled to the second mixer to receive the current control signal and produce a LNA control signal that is coupled to the LNA to control a bias current of the LNA, wherein cross modulation associated with the received RF signal is reduced.

6. An adaptive system for use with a radio receiver to adapt to interfering signals associated with a received RF signal, the radio receiver includes an LNA to receive the RF signal and produce an amplified signal that is coupled to a down-converting mixer that produces a mixer output, the adaptive system comprises:

a peak detector coupled to receive the mixer output to produce a peak signal;

an integrator coupled to the peak detector to receive the peak signal and produce an integrated signal; and

a second mixer coupled to the integrated signal and a receiver gain control signal to produce a VCO current control signal that is coupled to a VCO associated with a PLL that drives the down-converting mixer, wherein reciprocal mixing associated with the received RF signal is reduced by adjustment of the VCO associated with the PLL.

7. The adaptive system of claim 6, wherein the VCO control current signal is coupled to the VCO associated with the PLL via a VCO control circuit.

8. The adaptive system of claim 6, wherein the peak detector comprises a diode element.

9. An adaptive system for use with a radio receiver to adapt to interfering signals associated with a received RF signal, the radio receiver includes an LNA to receive the RF signal and produce an amplified signal that is coupled to a down-converting mixer that produces a mixer output, the adaptive system comprises:

a nonlinear element coupled to receive the mixer output to produce a peak signal;

an integrator coupled to the non-linear element to produce an integrator output; and

a second mixer coupled to receive the integrator output and a receiver power indicator to produce a receive control signal.

10. The adaptive system of claim 9, wherein the receive control signal is coupled to a receive control circuit, and wherein an output of the receive control circuit is coupled to the down-converting mixer to adjust the down-converting mixer in order to reduce intermodulation distortion.

11. A method for providing an adaptive system for use with a radio receiver to adapt to interfering signals associated with a received RF signal, the radio receiver includes an LNA to receive the RF signal and produce an amplified signal that is coupled to a down-converting mixer that produces a mixer output, the method comprising steps of:

deriving a peak signal from the mixer output;

integrating the peak signal to produce an integrated signal;

mixing the integrated signal and a transmit power indicator to produce a current control signal; and

controlling a bias current of the LNA with the current control signal, wherein cross modulation associated with the received RF signal is reduced.

12. A method for providing an adaptive system for use with a radio receiver to adapt to interfering signals associated with a received RF signal, the radio receiver includes an LNA to receive the RF signal and produce an amplified signal that is coupled to a down-converting mixer that produces a mixer output, the method comprising steps of:

deriving a peak signal from the mixer output;

integrating the peak signal to produce an integrated signal;

mixing the integrated signal and a receive power indicator to produce a VCO control signal; and

controlling a VCO based on the VCO control signal, wherein the VCO is associated with a PLL coupled to the down-converting mixer, and wherein the reciprocal mixing associated with the received RF signal is reduced by adjustment of the VCO associated with the PLL.

13. A method for providing an adaptive system for use with a radio receiver to adapt to interfering signals associated with a received RF signal, the radio receiver includes an LNA to receive the RF signal and produce an amplified signal that is coupled to a down-converting mixer that produces a mixer output, the method comprising steps of:

deriving a peak signal from the mixer output;

integrating the peak signal to produce an integrated signal;

mixing the integrated signal and a receive power indicator to produce a receive control signal; and

controlling the down-converting mixer based on the receive control signal, wherein intermodulation distortion associated with the received RF signal is reduced.