LNA control-circuit for receive closed loop automatic gain control

• US 6,324,387 B1
• Filed: 12/29/1998
• Issued: 11/27/2001
• Est. Priority Date: 12/29/1998
• Status: Expired due to Fees

• Current Assignee: Philips Electronics North America Corporation (Koninklijke Philips N.V.)
• Original Assignee: Philips Electronics North America Corporation (Koninklijke Philips N.V.)
• Inventors: Rouphael, Antoine J., Motamed, Mariam, Kamgar, Farbod
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): West, Lewis G.
• Application Number:
  US09/222,400
• Time in Patent Office: 1,064 Days
• Field of Search: 455/232.1, 455/234.1, 455/240.1, 455/246.1, 455/247.1, 455/250.1, 455/127, 455/522, 455/234.2, 375/345
• US Class Current: 455/234.1
• CPC Class Codes: H03G 3/3052 in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver H03G3/32, H03G3/34 take precedence

Abstract

A controlled receive device is disclosed having an amplifier circuit, which receives an input signal, and a control circuit which receives the input signal and outputs a controlled signal to a receiver. The receiver outputs an output signal. A controller varies the gain of the amplifier circuit in response to levels of the controlled signal and the output signal. The control circuit outputs a controlled indicator signal indicative of a level of the controlled signal and the receiver outputs an output indicator signal indicative of the output signal level. The controlled indicator signal and the output indicator signal are compared using comparators, to respective reference or threshold levels for producing control signals used by the controller for varying the amplifier gain.

Claims

1. A controlled receive device comprising:

an amplifier circuit which receives an input signal;

a control circuit which receives said input signal and outputs a controlled signal;

a receiver circuitry which receives said controlled signal and outputs an output signal; and

a controller which varies a gain of said amplifier circuit in response to a controlled signal level of said controlled signal and an output signal level of said output signal, wherein said controller decreases said gain when said output signal is less than an output threshold level and said controlled signal is greater than an indicator threshold level.

2. The controlled receive device of claim 1, wherein said controller is connected in a first feedback loop of said amplifier circuit and said receiver and in a second feedback loop of said amplifier circuit and said control circuit.

3. The controlled receive device of claim 1, wherein said amplifier circuit includes a low noise amplifier having a variable gain.

4. The controlled receive device of claim 1, wherein said control circuit outputs a controlled indicator signal indicative of said controlled signal level and said receiver outputs an output indicator signal indicative of said output signal level, said controlled indicator signal and said output indicator signal being compared to respective reference levels for producing control signals used by said controller for varying said gain of said circuit amplifier.

5. The controlled receive device of claim 1, further comprising a first comparator which compares a controlled indicator signal, which is received from said control circuit and is indicative of said controlled signal level, with a first predetermined value and provides a first control signal to said controller;

and a second comparator which compares an output indicator signal, which is received from said receiver and is indicative of said output signal level, with a second predetermined value and provides a second control signal to said controller.

6. The controlled receive device of claim 1, wherein said controller increases said gain when said output signal is less than an output threshold level and said controlled signal is less than an indicator threshold level.

7. The controlled receive device of claim 1, wherein said controller keeps said gain unchanged when said output signal is greater than an output threshold level.

8. The controlled receive device of claim 1, wherein said output signal level is a sum of pilot power signals from fingers of said receiver.

9. A receive device comprising:

means for increasing a gain of an amplifier circuit which receives an input signal when a controlled signal from a control circuit connected to said amplifier circuit is less than a controlled threshold level and an output signal of a receiver connected to said control circuit is less than an output threshold level; and

means for decreasing said gain when said controlled signal is greater than said controlled threshold level and said output signal is less than said output threshold level.

10. The receive device of claim 9 further comprising means for maintaining said gain unchanged when said output signal is greater than said output threshold level.

11. The receive device of claim 9, wherein said output signal is a sum of pilot power signals from fingers of said receiver.

12. A method for controlling a controlled receive device comprising the steps of:

increasing a gain of an amplifier circuit which receives an input signal when a controlled signal from a control circuit connected to said amplifier circuit is less than a controlled threshold level and an output signal of a receiver connected to said control circuit is less than an output threshold level;

decreasing said gain when said controlled signal is greater than said controlled threshold level and said output signal is less than said output threshold level; and

maintaining said gain unchanged when said output signal is greater than said output threshold level.

13. The method of claim 12, wherein said output signal is a sum of pilot power signals from fingers of said receiver.