Dynamic performance control of broadband tuner

• US 7,783,272 B2
• Filed: 06/29/2006
• Issued: 08/24/2010
• Est. Priority Date: 06/29/2006
• Status: Active Grant

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: Microtune, Inc. (Qualcomm, Inc.)
• Inventors: Magnusen, Timothy M.
• Primary Examiner(s): Tran; Pablo N
• Application Number:
  US11/477,313
• Publication Number:
  US 20080003966A1
• Time in Patent Office: 1,517 Days
• Field of Search: 455/232.1, 455/234.2, 455/245.1, 455/245.2, 455/247.1, 455/250.1, 455/251.1, 455/296, 455/303, 455/324, 455/343.1, 455/226.1, 455/226.2, 455/334, 455/340, 455/341, 455/574, 455/248.1, 455/241.1, 455/240.1, 455/522, 455/127.1, 455/194.2, 455/195.1, 455/311, 375/345, 375/346, 330/254, 330/282, 330/296, 348/707
• US Class Current: 455/232.1
• CPC Class Codes: H03F 1/0261 with control of the polarisation voltage or current, e.g. gliding Class A
• CPC Class Codes: H03F 2200/105 A non-specified detector of the power of a signal being used in an amplifying circuit
• CPC Class Codes: H03F 2200/228 A measuring circuit being coupled to the input of an amplifier
• CPC Class Codes: H03F 3/45197 Pl types H03F3/45224, H03F3/45251 take precedence
• CPC Class Codes: H04N 7/102 Circuits therefor, e.g. noise reducers, equalisers, amplifiers H04N7/108 takes precedence

Abstract

A broadband signal amplifier includes one of more broadband amplifier circuits, each dynamically controlled in response to a total power level of signals applied thereto to reduce linearity in response to a reduction of input signal strength. A filter may couple the output of the broadband amplifier circuits to each other to form a tandem arrangement. Power detectors are connected to detect and provide outputs indicative of the total power levels of the signals applied to respective broadband amplifiers. A control unit is connected to and receives the output from the power detectors and, in response, provides a control signals to the broadband amplifier circuit so as to operate each over portions of their operating characteristic curves that provide only that degree of linearity necessary to limit distortion to a predetermined or dynamically adjustable maximum acceptable level.

Claims

1. A circuit for controlling an operation of a broadband amplifier circuit, comprising:

a power detector connected to provide an output indicative of a total signal power level of an input signal applied to the broadband amplifier circuit; and

a control unit receiving said output from said power detector and, in response, providing a control signal to the broadband amplifier circuit, said control signal adjusting a performance attribute of said broadband amplifier circuit to dynamically maintain, without substantially exceeding, minimum allowable performance criteria;

wherein said output indicative of a total signal power level of an input signal is derived by measuring the output signal from said amplifier circuit and subtracting a gain factor of said amplifier circuit.

2. The circuit according to claim 1 wherein said performance criteria corresponds to a linearity of the broadband amplifier circuit.

3. The circuit according to claim 2 wherein said control signal operates to cause said linearity of the broadband amplifier circuit to vary in direct relationship to said total signal power level of said input signal.

4. The circuit according to claim 1 wherein said performance criteria corresponds to a distortion of the broadband amplifier circuit.

5. The circuit according to claim 4 wherein said control signal operates to cause said distortion of the broadband amplifier circuit to vary in inverse relationship to said total signal power level of said input signal.

6. The circuit according to claim 1 wherein said performance attribute corresponds to a quiescent point of the broadband amplifier circuit.

7. The circuit according to claim 1 wherein said control signal adjusts a bias level supplied to a component of the broadband amplifier circuit.

8. The circuit according to claim 1 further controlling an operation of a second broadband amplifier circuit, said circuit further comprising:

a second power detector connected to provide an output indicative of a total signal power level of an input signal applied to the second broadband amplifier circuit,

said a control unit receiving said output from said second power detector and, in response, providing a control signal to the second broadband amplifier circuit, said control signal supplied to said second broadband amplifier circuit adjusting a performance attribute thereof to dynamically maintain without substantially exceeding minimum allowable performance criteria of said second broadband amplifier circuit.

9. An amplifier comprising:

a broadband amplifier circuit connect to receive and amplify a signal level of an input signal and provide as an output an amplified signal;

a power detector connected to the input of said amplifier circuit and configured to provide an output indicative of a total signal power level of said input signal; and

a control unit receiving said output from said power detector and, in response, providing a control signal to said broadband amplifier circuit, said control signal adjusting a performance attribute of said broadband amplifier circuit to dynamically maintain without substantially exceeding minimum allowable performance criteria.

10. The amplifier according to claim 9 wherein said performance criteria corresponds to a linearity of the broadband amplifier circuit.

11. The amplifier according to claim 10 wherein said control signal operates to cause said linearity of the broadband amplifier circuit to vary in direct relationship to said total signal power level of said input signal.

12. The amplifier according to claim 9 wherein said performance criteria corresponds to a distortion of the broadband amplifier circuit.

13. The amplifier according to claim 12 wherein said control signal operates to cause said distortion of the broadband amplifier circuit to vary in inverse relationship to said total signal power level of said input signal.

14. The amplifier according to claim 9 wherein said performance attribute corresponds to a quiescent point of said broadband amplifier circuit.

15. The amplifier according to claim 9 wherein said control signal adjusts a bias level supplied to an active component of said broadband amplifier circuit.

16. The amplifier according to claim 9 further comprising:

a filter connect to an output of said broadband amplifier circuit and receiving said output signal, said filter attenuating signals having frequencies offset from a center frequency of said filter to provide a filtered signal output;

a second power detector connected to provide an output indicative of a total signal power level of said filtered signal output from said filter; and

a second broadband amplifier circuit connect to said filter and receiving said filtered signal output, said second broadband amplifier circuit configured to amplify said filtered signal output to provide an amplified filtered signal,

said a control unit receiving said output from said second power detector and, in response, providing a control signal to said second broadband amplifier circuit, said control signal supplied to said second broadband amplifier circuit adjusting a performance attribute thereof to dynamically maintain without substantially exceeding minimum allowable performance criteria of said second broadband amplifier circuit.

17. A television tuner comprising:

an input circuit connected to receive a broadband input signal and providing a broadband output signal;

a power detector connected to provide an output indicative of a total signal power level of said broadband input signal, said power detector configured to subtract a gain factor resulting from said input circuit to provide said output indicative of a total input signal power level;

a control unit receiving said output from said power detector and, in response, providing a control signal to the input circuit, said control signal adjusting a performance attribute of said input circuit to dynamically maintain, without substantially exceeding, minimum allowable performance criteria; and

a detector configured to demodulate a signal carried by said broadband output signal to provide a baseband signal.

18. The television tuner according to claim 17 wherein said input circuit comprises a broadband amplifier circuit.

19. A method of controlling an operation of a broadband amplifier circuit, comprising the steps of:

detecting a total signal power level of an input signal applied to the broadband amplifier circuit; and

adjusting a performance attribute of said broadband amplifier circuit in response to said total signal power level to dynamically maintain, without substantially exceeding, minimum allowable performance criteria.

20. The method according to claim 19 wherein said performance criteria corresponds to a linearity of the broadband amplifier circuit.

21. The method according to claim 20 wherein said adjusting step causes said linearity of the broadband amplifier circuit to vary in direct relationship to said total signal power level of said input signal.

22. The method according to claim 19 wherein said performance criteria corresponds to a distortion of the broadband amplifier circuit.

23. The method according to claim 22 wherein said adjusting step causes said distortion of the broadband amplifier circuit to vary in inverse relationship to said total signal power level of said input signal.

24. The method according to claim 19 wherein said adjusting step varies a quiescent point of the broadband amplifier circuit.

25. The method according to claim 19 wherein said adjusting step includes adjusting a bias level supplied to a component of the broadband amplifier circuit.

26. A method of amplifying a broadband signal comprising the steps of:

detecting a total input signal power level of the broadband signal;

determining a value of an amplifying operating parameter necessary to maintain, without substantially exceeding, minimum allowable performance criteria for amplifying the broadband signal; and

amplifying said broadband signal utilizing said value of said amplifying operating parameter.

27. The method according to claim 26 wherein said performance criteria corresponds to a linearity of said amplifying step.

28. The method according to claim 27 wherein said determining step causes said linearity of amplifying step to vary in direct relationship to said total signal power level of the broadband signal.

29. The method according to claim 26 wherein said performance criteria corresponds to a distortion of said amplifying step.

30. The method according to claim 29 wherein said determining step causes said distortion of amplifying step to vary in inverse relationship to said total signal power level of the broadband signal.