Broadband integrated television tuner

• US 7,868,704 B2
• Filed: 05/12/2009
• Issued: 01/11/2011
• Est. Priority Date: 04/21/1995
• Status: Expired due to Fees

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: Microtune, Inc. (Qualcomm, Inc.)
• Inventors: Clayton, Kenneth W., Taddiken, Albert H., Birleson, S. Vincent
• Primary Examiner(s): Sajous; Wesner
• Application Number:
  US12/464,759
• Publication Number:
  US 20090219451A1
• Time in Patent Office: 609 Days
• Field of Search: None
• US Class Current: 331/16
• CPC Class Codes: H03D 7/161 all the frequency changers being connected in cascade
• CPC Class Codes: H03J 1/005 in a loop
• CPC Class Codes: H03J 2200/14 Tunable filter in receiver contributing to image rejection
• CPC Class Codes: H03J 7/065 the counter or frequency divider being used in a phase locked loop
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/4263 involving specific tuning arrangements, e.g. two tuners
• CPC Class Codes: H04N 5/4446 IF amplifier circuits specially adapted for B&W TV RF amplifiers in general H03F3/189
• CPC Class Codes: H04N 5/455 Demodulation-circuits
• CPC Class Codes: H04N 5/50 Tuning indicators; Automatic tuning control
• CPC Class Codes: H04N 5/52 Automatic gain control
• CPC Class Codes: H04N 5/60 for the sound signals

Abstract

A broadband integrated television receiver for receiving a standard antenna or cable input and outputting an analog composite video signal and composite audio signal is disclosed. The receiver employs an up-conversion mixer and a down-conversion mixer in series to produce an IF signal. An IF filter between the mixers performs coarse channel selection. The down-conversion mixer may be an image rejection mixer to provide additional filtering. The received RF television signals are converted to a standard 45.75 MHz IF signal for processing on-chip by additional circuitry.

Claims

1. A receiver comprising:

a first mixer having a first input for receiving a radio frequency (RF) signal and a second input coupled to a first local oscillator signal having a first operating frequency;

a second mixer having a first input in communication with an output of said first mixer and a second input coupled to a second local oscillator signal having a second operating frequency; and

a digital interface providing control of the operating frequency of at least one of said first and second local oscillator signals, wherein said first mixer, said second mixer, and said digital interface are located on a single integrated circuit substrate.

2. The receiver of claim 1 further comprising:

a first filter having an input coupled to the output of said first mixer and an output coupled to the first input of said second mixer; and

a second filter having an input coupled with an output of said second mixer.

3. The receiver of claim 1 further comprising:

a coherent oscillator circuit having an input in communication with an output of said second filter, and

a frequency discriminator having a first input in communication with an output of said coherent oscillator circuit, wherein said frequency discriminator generates a tuning error signal for said digital interface in response to the output of said coherent oscillator circuit.

4. The receiver of claim 1 wherein said receiver operates at a single voltage level.

5. The receiver of claim 1 further comprises a first amplifier providing input to said first mixer and a second amplifier having an input in communication with an output of said second filter, wherein said first and second amplifiers act in conjunction to control the overall signal level of said receiver.

6. The receiver of claim 2 wherein said second mixer operates as an image rejection mixer when an output signal of said first filter is not attenuated to a desired frequency.

7. The receiver of claim 1 wherein said first operating frequency is selected such that said first mixer performs an up-conversion of said received RF signal.

8. The receiver of claim 7 wherein said second operating frequency is selected such that said second mixer performs a down-conversion of a first intermediate frequency (IF) signal.

9. The receiver of claim 1 wherein said first operating frequency and said second operating frequency are selected such that said second mixer generates a second IF signal with a fixed frequency.

10. The receiver of claim 1 further comprising an antenna providing an input signal for said first mixer, said antenna capable of being connected directly to a standard coaxial cable, thereby allowing both antenna and cable television applications.

11. The receiver of claim 1, wherein said receiver is included in a personal computer and is operative to receive and display television signals.

12. The receiver of claim 1, wherein said RF signal comprises a plurality of channels.

13. A method for receiving signals performed by a signal tuning circuit, the method comprising:

converting a received RF signal to first intermediate frequency (IF) signal by mixing said signal and a first local oscillator signal having a first operating frequency;

performing selection of said first IF signal by removing channels having frequencies outside of a desired band;

converting said first IF signal to a second IF signal by mixing said filtered first IF signal with a second local oscillator signal having a second operating frequency;

controlling of the operating frequency of at least one of said first local oscillator signal and said second local oscillator signal by applying a digital signal;

performing fine selection of said second IF signal such that only one channel remains in said second IF signal; and

processing said filtered second IF signal with a coherent oscillator circuit.

14. The method of claim 13 further comprising:

generating a tuning error signal, for said control of the operating frequency of the one of said first local oscillator signal and said second local oscillator, in response said processed second IF signal provided by said coherent oscillator circuit.

15. The method of claim 13 wherein said method is performed at a single voltage level.

16. A method for receiving signals performed by a signal tuning circuit, the method comprising:

converting a received RF signal to first intermediate frequency (IF) signal by mixing said signal and a first local oscillator signal having a first operating frequency;

performing selection of said first IF signal by removing channels having frequencies outside of a desired band;

converting said first IF signal to a second IF signal by mixing said filtered first IF signal with a second local oscillator signal having a second operating frequency;

controlling of the operating frequency of at least one of said first local oscillator signal and said second local oscillator signal by applying a digital signal;

selecting said first operating frequency such that conversion of said received RF signal is accomplished by an up-conversion mixing of said received RF signal with said first local oscillator signal; and

selecting said second operating frequency such that conversion of said first IF signal is accomplished by an down-conversion mixing of said first IF signal with said second local oscillator signal.

17. A receiver comprising:

a first amplifier receiving an RF signal, wherein said first amplifier is a low-noise amplifier;

a first mixer having a first input coupled to said first amplifier and a second input coupled to a first local oscillator signal having a first operating frequency, wherein said first mixer is in communication with a first filter;

a second mixer having a first input coupled to an output of said first filter and a second input coupled to a second local oscillator signal having a second operating frequency, wherein said second mixer is in communication with a second amplifier;

a second filter having an input coupled to an output of said second amplifier; and

a third amplifier in communication with said second filter;

wherein the second filter is external to a single integrated circuit substrate on which at least said first amplifier and said first and second mixers are located.

18. The receiver of claim 17 further comprises:

a coherent oscillator circuit in communication with an output of said second amplifier, wherein said coherent oscillator circuit is located on said single integrated circuit substrate.

19. The receiver of claim 17 further comprises:

a decoder external to said single integrated circuit substrate, wherein said decoder is in communication with said second amplifier.

20. The receiver of claim 17 wherein said receiver is operable in a television.

21. A television receiver comprising:

a first amplifier receiving an RF signal;

a first mixer having a first input coupled to said first amplifier and a second input coupled to a first local oscillator signal having a first operating frequency;

a second mixer having a first input in communication with an output of said first mixer and a second input coupled to a second local oscillator signal having a second operating frequency;

a second amplifier receiving an output signal from said second mixer, wherein said second amplifier is an automatic gain control amplifier; and

a coherent oscillator circuit having an input coupled to said second amplifier and an output coupled to an automatic gain control circuit in communication with a video detector, wherein said automatic gain control circuit is capable of controlling a gain of said television receiver by adjusting gains of said first and second amplifiers.

22. The television receiver of claim 21 wherein said gain adjustment is made based on an output signal from said video detector.

23. The television receiver of claim 21 wherein at least two of said low noise amplifier, said first and second mixers, said first and second filters, said automatic gain control amplifier, said coherent oscillator circuit, said video detector, and said automatic gain control circuit are located on a single integrated circuit substrate.

24. The television receiver of claim 21 further comprises:

a decoder external to said single integrated circuit and in communication with said automatic gain control circuit, wherein said gain adjustment is made based on an output signal from said decoder.

25. A receiver comprising:

a receiver input coupled to an RF signal source;

a first local oscillator signal having a first operating frequency;

a first mixer having a first input coupled to said receiver input and a second input coupled to said first local oscillator signal;

a second mixer having a first input coupled to an output of said first mixer and a second input coupled to a second local oscillator signal having a second operating frequency, wherein a first and a second phase locked loop provide local oscillator signal inputs for a third phase locked loop to produce said second local oscillator signal; and

a frequency synthesizer for generating local oscillator frequency inputs to said first and second phase locked loops, wherein loop bandwidths of said first and second phase locked loops are independent of a step size of said frequency synthesizer.

26. The receiver of claim 25 wherein said first and third phase locked loops have bandwidths of 300-500 KHz and said second phase locked loop has bandwidth of 200-300 KHz.

27. The receiver of claim 25 wherein said second and third phase locked loops have bandwidths of 300-500 KHz and said first phase locked loop has bandwidth of 200-300 KHz.