Highly integrated television tuner on a single microcircuit

• US 5,737,035 A
• Filed: 04/21/1995
• Issued: 04/07/1998
• Est. Priority Date: 04/21/1995
• Status: Expired due to Term

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: Microtune, Inc. (Qualcomm, Inc.)
• Inventors: Rotzoll, Robert Rudolf
• Primary Examiner(s): HSIA, SHERRIE Y
• Application Number:
  US08/426,080
• Time in Patent Office: 1,082 Days
• Field of Search: 455/302, 455/315, 455/339, 455/179.1, 348/725, 348/726, 348/731
• US Class Current: 348/725
• CPC Class Codes: H03D 3/007 by converting the oscillations into two quadrature related signals H03D3/245 takes precedence
• CPC Class Codes: H03D 7/161 all the frequency changers being connected in cascade
• CPC Class Codes: H03J 7/02 Automatic frequency control H03J7/18 takes precedence

Abstract

There is disclosed a fully integrated television receiver for receiving a standard antenna or cable input and outputting a standard video baseband signal and a standard audio baseband signal. The receiver employs an up-conversion mixer and a down-conversion image-rejection mixer in series to produce an on-chip IF signal. Audio detection of the IF signal is performed via an audio delay-locked loop operating in quadrature to the audio FM signal. Video detection of the IF signal is performed by frequency mixing the IF signal with the extracted video carrier of the IF signal. Variable load drive capability is provided for both the video output and the audio output.

Claims

1. A television receiver comprising:

a receiver input coupled to an RF signal source;

a first reference 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 reference signal;

a second reference signal having a second operating frequency; and

a second mixer having a first input coupled directly to an output of said first mixer and a second input coupled to said second reference signal, wherein said second mixer is an image rejection mixer.

2. The television receiver as set forth in claim 1 wherein said first mixer is a subtractive mixer.

3. The television receiver as set forth in claim 2 wherein a minimum frequency value of said first reference signal is greater than an input cutoff frequency of an RF signal received from said RF signal source.

4. The television receiver as set forth in claim 1 wherein said first operating frequency is variable between a minimum frequency value and a maximum frequency value.

5. The television receiver as set forth in claim 4 wherein said first mixer subtractively mixes said first reference signal and an RF signal received from said RF signal source to thereby generate a first IF signal on said first mixer output.

6. The television receiver as set forth in claim 5 wherein a selected carrier frequency in said RF signal appears at a first predetermined frequency in said first IF signal.

7. The television receiver as set forth in claim 6 wherein said first predetermined frequency is 1200 Megahertz.

8. The television receiver as set forth in claim 6 wherein said selected carrier frequency is selected by varying said first operating frequency.

9. The television receiver as set forth in claim 1 wherein said first mixer is coupled to said receiver input by an input filter which filters out all frequency components in said RF signal above an input cutoff frequency.

10. The television receiver as set forth in claim 9 wherein said minimum frequency value of said first reference signal is greater than said input cutoff frequency.

11. The television receiver as set forth in claim 6 wherein said second mixer mixes said second reference signal and said first IF signal to thereby generate a second IF signal containing all of the channels of information as contained in said RF signal.

12. The television receiver as set forth in claim 11 wherein said second operating frequency is fixed.

13. The television receiver as set forth in claim 12 wherein said second mixer rejects from said second IF signal an image signal of said second reference signal.

14. The television receiver as set forth in claim 13 wherein said selected carrier frequency in said RF signal appears at a second predetermined frequency in said second IF signal.

15. The television receiver as set forth in claim 13 wherein said minimum frequency value of said first reference signal is greater than an input cutoff frequency of said RF signal.

16. The television receiver as set forth in claim 1 further comprising a first IF signal generated by said first mixer wherein said second mixer mixes said second reference signal and said first IF signal to generate a second IF signal containing all of the channels of information as contained in an RF signal received from said RF signal source.

17. The television receiver as set forth in claim 16 wherein said second operating frequency is fixed.

18. The television receiver as set forth in claim 17 wherein said second mixer rejects from said second IF signal an image signal of said first IF signal.

19. The television receiver as set forth in claim 18 wherein a selected carrier frequency in an RF signal received from said RE signal source appears at a first predetermined frequency in said first IF signal and at a second predetermined frequency in said second IF signal.

20. The television receiver as set forth in claim 19 wherein said second predetermined frequency is a difference in frequency between said first predetermined frequency and said second operating frequency.

21. The television receiver as set forth in claim 20 wherein said second operating frequency is less than said first predetermined frequency and the frequency of said image signal rejected by said second mixer is less than said second operating frequency by an amount equal to said second predetermined frequency.

22. The television receiver as set forth in claim 20 wherein said first predetermined frequency is 1200 Megahertz, said second operating frequency is 1180 Megahertz, and said second predetermined frequency is 20 Megahertz.

23. A television receiver comprising:

a receiver input coupled to an RF signal source;

a first mixer physically located on an integrated circuit substrate having a first input coupled to said receiver input and a second input coupled to a first reference signal having a first operating frequency, wherein said first operating frequency is variable between a minimum frequency value and a maximum frequency value; and

a second mixer physically located on the same integrated circuit substrate as the first mixer and having a first input directly coupled without leaving the substrate to an output of said first mixer and a second input coupled to a second reference signal having a second operating frequency, wherein said second operating frequency is fixed.

24. The television receiver as set forth in claim 23 wherein said minimum frequency value is greater than an input cutoff frequency of an RF signal received from said RF signal source.

25. The television receiver as set forth in claim 24 wherein said first mixer subtractively mixes said RF signal and said first reference signal to thereby produce a first IF signal, wherein a selected carrier frequency in said RF signal appears at a first predetermined frequency in said first IF signal and said first predetermined frequency is greater than said selected carrier frequency.

26. The television receiver as see forth in claim 25 wherein said second mixer mixes said first IF signal and said second reference signal to thereby produce a second IF signal, wherein said selected carrier frequency appears in said second IF signal at a second predetermined frequency and said second predetermined frequency is less than said first predetermined frequency and said second operating frequency.

27. The television receiver as set forth in claim 26 wherein said second mixer rejects at least one image signal associated with said second operating frequency from said second IF signal.

28. A method of processing a received RF signal, the method comprising the steps of:

mixing the RF signal with a first reference signal having a first operating frequency to thereby produce a first IF signal; and

mixing the first IF signal with a second reference signal having a second operating frequency to thereby produce a second IF signal, said mixing of the first IF signal with the second reference signal occurring prior to eliminating any channels from the first IF signal, wherein said RF signal mixing and said first IF signal mixing operations are accomplished on the same integrated circuit substrate.

29. The method as set forth in claim 28 including the further step of filtering out of the RF signal all frequency components above an input cutoff frequency.

30. The method as set forth in claim 29 wherein the first operating frequency is greater than the input cutoff frequency.

31. The method as set forth in claim 30 wherein the step of mixing the RF signal with the first reference signal is a subtractive mixing of the RF signal and the first reference signal.

32. The method as set forth in claim 31 wherein the step of mixing the RF signal with the first reference signal is an up-conversion mixing, wherein a selected carrier frequency in the RF signal appears in the first IF signal at a frequency higher than the RF signal.

33. The method as set forth in claim 28 wherein the step of mixing the first IF signal with the second reference signal further includes the substep of removing from the second IF signal at lease one image signal associated with the first IF signal.

34. A method of processing a received RF signal, the method comprising the steps of:

filtering all frequency components above an input cutoff frequency out of the received RF signal to thereby produce a first filtered signal;

amplifying the first filtered signal;

subtractively mixing the amplified first filtered signal with a first reference signal having a first operating frequency to thereby produce a first IF signal; and

mixing the first IF signal with a second reference signal having a second operating frequency to thereby produce a second IF signal, said mixing of the first IF signal with the second reference signal occurring prior to eliminating any channels from the first IF signal.

35. The method as set forth in claim 34 wherein the first operating frequency is greater than the input cutoff frequency.

36. The method as set forth in claim 35 wherein the step of mixing the RF signal with the first reference signal is an up-conversion mixing, wherein a selected carrier signal in the RF signal appears in the first IF signal at a first predetermined frequency and wherein the first predetermined frequency is higher than the RF signal.

37. The method as set forth in claim 34 wherein the step of mixing the first IF signal with the second reference signal further includes the substep of removing from the second IF signal at least one image signal associated with the first IF signal.

38. The method as set forth in claim 34 wherein the step of mixing the first IF signal with the second reference signal is a down conversion mixing, wherein a selected carrier signal appearing in the first IF signal at a first predetermined frequency appears in the second IF signal at a second predetermined frequency and wherein the second predetermined frequency is lower than the first IF signal.

39. The method as set forth in claim 34 including the further step of filtering the second IF signal with a bandpass filter.

40. The method as set forth in claim 39 wherein the bandpass filter has a passband between 15 Megahertz and 21 Megahertz.

41. The method as set forth in claim 39 wherein the bandpass filter is a Nyquist slope filter having a cutoff frequency of 20 Megahertz.

42. A television receiver comprising:

an input filter coupled to an RF signal source;

a first amplifier coupled to an output of said input filter;

a first mixer having a first input and a second input, wherein said first input of said first mixer is coupled to an output of said first amplifier;

a first oscillator coupled to said second input of said first mixer, wherein said first oscillator generates a first reference signal having a first operating frequency;

a second mixer having a first input and a second input, wherein said first input of said second mixer is coupled directly to an output of said first mixer without the connection of a filter therebetween;

a second oscillator coupled to said second input of said second mixer, wherein said second oscillator generates a second reference signal having a second operating frequency; and

a second filter coupled to an output of said second mixer.

43. The television receiver as set forth in claim 42 wherein said input filter is a low-pass filter having a -3 dB cutoff frequency of 900 Megahertz.

44. The television receiver as set forth in claim 42 wherein said first amplifier is a transconductance amplifier having a noise figure between 4.5 dB and 5.4 dB.

45. The television receiver as set forth in claim 42 wherein the gain of said first amplifier is automatically controlled by an automatic gain control circuit of said television receiver.

46. The television receiver as set forth in claim 42 wherein said first mixer is an up-converter which subtractively mixes a filtered and amplified RF signal having a maximum cutoff frequency with said first reference signal to thereby generate a first IF signal, wherein a lower limit of said first operating frequency is greater than said maximum cutoff frequency.

47. The television receiver as set forth in claim 42 wherein said first oscillator is a phase-locked synthesizer and said first operating frequency has an upper limit of 2100 Megahertz and a lower limit of 1200 Megahertz.

48. The television receiver as set forth in claim 42 wherein said second mixer is an image-rejection mixer which down-converts a first IF signal outputted from said first mixer to thereby generate a second IF signal.

49. The television receiver as set forth in claim 42 wherein said second oscillator is a fixed tuned-frequency synthesizer and said second operating frequency is approximately 1180 Megahertz.

50. The television receiver as set forth in claim 42 wherein said second filter is a bandpass filter having an upper passband limit of 20.75 Megahertz and a lower passband limit of 15.8 Megahertz.

51. The television receiver as set forth in claim 42 wherein said second filter is a Nyquist slope filter.

52. The television receiver as set forth in claim 51 wherein said second filter has a -6 dB gain point at a visual carrier frequency of an IF signal generated by said second mixer.

53. The television receiver as set forth in claim 52 wherein said visual carrier frequency is approximately 20 Megahertz and said second filter has a passband corner frequency of approximately 19.25 Megahertz.

54. The television receiver as set forth in claim 52 wherein said second filter is automatically tuned by measuring the level of synchronization pulses on a input of said second filter and on an output of said second filter and adjusting a cut-off frequency of said second filter so that there is a 6 dB loss on said output of said second filter.

55. The television receiver as set forth in claim 42 wherein said television receiver further comprises:

a second amplifier coupled to an output of said second filter.

56. The television receiver as set forth in claim 55 wherein the gain of said second amplifier is automatically controlled by an automatic gain control circuit of said television receiver.

57. The television receiver as set forth in claim 55 wherein said television receiver further comprises:

a third filter coupled to an output of said second amplifier, wherein said third filter is a bandpass filter for extracting a video carrier signal from an output signal of said second amplifier; and

a third mixer having a first input and a second input, wherein said first input of said third mixer is coupled to said output of said second amplifier and said second input of said third mixer is coupled to an output of said third filter and wherein an output signal on an output of said third mixer is a video baseband signal.

58. The television receiver as set forth in claim 57 wherein said second input of said third mixer is coupled to said third filter by amplitude limiting circuitry, wherein said amplitude limiting circuitry provides a fixed-amplitude reference carrier signal to said third mixer.

59. The television receiver as set forth in claim 57 wherein said television receiver further comprises frequency detection circuitry having a first input and a second input, wherein said first input of said frequency detection circuitry is coupled to said output of said third filter and said second input of said frequency detection circuitry is coupled to a third reference signal having a third operating frequency.

60. The television receiver as set forth in claim 59 wherein said frequency detection circuitry compares the frequency of said video carrier signal to said third operating frequency to thereby produce an output control signal, wherein said output control signal is used to control said first operating frequency of said first reference signal generated by said first oscillator.

61. The television receiver as set forth in claim 57 wherein said television receiver further comprises a fourth filter coupled to said output of said third mixer and wherein said fourth filter is a low-pass filter that cuts off all signal components higher in frequency than said video baseband signal.

62. The television receiver as set forth in claim 61 wherein said television receiver further includes a clamping circuit for clamping synchronization pulses in said video baseband signal from said fourth filter.

63. The television receiver as set forth in claim 62 wherein said television receiver further comprises a noise inverter circuit coupled to said clamping circuit, wherein said noise inverter circuit removes transient noise pulses from said video baseband signal.

64. The television receiver as set forth in claim 63 wherein said transient noise pulses comprise transient noise pulses that cause said video baseband signal to drop below a blanking level of said video baseband signal.

65. The television receiver as set forth in claim 63 wherein said transient noise pulses comprise transient noise pulses that cause said video baseband signal to rise above a 108 IRE white level of said video baseband signal.

66. The television receiver as set forth in claim 57 wherein said television receiver further comprises an automatic gain control circuit coupled to said output of said third mixer, wherein said automatic gain control circuit controls the gain of said second amplifier.

67. The television receiver as set forth in claim 66 wherein said automatic gain control circuit controls the gain of said first amplifier.

68. The television receiver as set forth in claim 66 wherein said automatic gain control circuit comprises a sample-and-hold circuit coupled to a first input of a differential amplifier.

69. The television receiver as set forth in claim 68 wherein a second input of said differential amplifier is coupled to a reference voltage equal to an output blanking level of a standard NTSC video baseband signal.

70. The television receiver as set forth in claim 57 wherein said television receiver further comprises a video output buffer amplifier coupled to said output of said third mixer.

71. The television receiver as set forth in claim 70 wherein said video output buffer amplifier comprises a linear transconductance amplifier.

72. The television receiver as set forth in claim 71 wherein said video output buffer amplifier further comprises blanking means for setting an output signal of said video output buffer amplifier to a video blanking level.

73. The television receiver as set forth in claim 72 wherein said video output buffer amplifier further comprises switching means for varying an output load of said video output buffer amplifier.

74. The television receiver as set forth in claim 55 wherein said television receiver further comprises a third filter coupled to an output of said second amplifier, wherein said third filter is a narrow-band filter for filtering an audio component signal from a video output signal on said output of said second amplifier.

75. The television receiver as set forth in claim 74 wherein said third filter has a center frequency of 15.5 Megahertz and a band width of 300 Kilohertz.

76. The television receiver as set forth in claim 74 wherein said television receiver further comprises:

audio phase detector circuitry coupled to an output of said third filter; and

a third mixer having a first input and a second input, wherein said first input of said third mixer is coupled to said output of said third filter and said second input of said third mixer is coupled to an output of said audio phase detector circuitry.

77. The television receiver as set forth in claim 76 wherein said audio phase detector circuitry comprises a delay-locked loop, wherein an output signal of said delay-locked loop operates in phase quadrature with a center frequency of said audio component signal on said output of said third filter.

78. The television receiver as set forth in claim 76 wherein said television receiver further comprises a fourth filter coupled to an output of said third mixer, wherein said fourth filter is a low-pass filter with a cut-off frequency of 120 Kilohertz.

79. The television receiver as set forth in claim 76 wherein said television receiver further comprises an audio output buffer amplifier coupled to an output of said third mixer.

80. The television receiver as set forth in claim 79 wherein said audio output buffer amplifier comprises a linear transconductance amplifier.

81. The television receiver as set forth in claim 79 wherein said audio output buffer amplifier further comprises muting means for setting an output signal of said audio output buffer amplifier to zero volts.

82. The television receiver as set forth in claim 80 wherein said audio output buffer amplifier further comprises switching means for varying an output load of said audio output buffer amplifier.

119. The television receiver as set forth in claim 42 wherein said input filter limits the frequencies passed to those at or below the highest channel in a desired frequency band.

83. A television receiver comprising:

a receiver input coupled to an RF signal source;

a first reference 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 reference signal;

a first bandpass filter coupled to an output of said first mixer;

the bandpass filter passing more than one channel and performing partial image rejection as well as limiting overall signal power levels to be processed by subsequent circuitry;

a second reference signal having a second operating frequency; and

an image rejection mixer having a first input coupled to an output of said first bandpass filter and a second input coupled to said second reference signal.

84. The television receiver as set forth in claim 83 wherein said first mixer is a subtractive mixer.

85. The television receiver as set forth in claim 84 wherein a minimum frequency value of said first reference signal is greater than an input cutoff frequency of an RF signal outputted from said RF signal source.

86. The television receiver as set forth in claim 83 wherein said first operating frequency is variable between a minimum frequency value and a maximum frequency value.

87. The television receiver as see forth in claim 86 wherein said first mixer subtractively mixes said first reference signal and an RF signal outputted from said RF signal source to thereby generate a first IF signal on said first mixer output.

88. The television receiver as set forth in claim 87 wherein a selected carrier frequency in said RF signal appears at a first predetermined frequency in said first IF signal.

89. The television receiver as set forth in claim 88 wherein said first predetermined frequency is 1200 Megahertz.

90. The television receiver as set forth in claim 88 wherein said selected carrier frequency is selected by varying said first operating frequency.

91. The television receiver as set forth in claim 87 wherein said first mixer is coupled to said receiver input by an input filter which filters out all frequency components in said RF signal above an input cutoff frequency.

92. The television receiver as set forth in claim 91 wherein said minimum frequency value of said first reference signal is greater than said input cutoff frequency.

93. The television receiver as set forth in claim 88 wherein said second mixer mixes said second reference signal and a first filtered signal on said output of said first bandpass filter to thereby generate a second IF signal.

94. The television receiver as set forth in claim 93 wherein said second operating frequency is fixed.

95. The television receiver as set forth in claim 94 wherein said selected carrier frequency in said RF signal appears at a second predetermined frequency in said second IF signal.

96. The television receiver as set forth in claim 94 wherein said minimum frequency value of said first reference signal is greater than an input cutoff frequency of said RF signal.

97. A television receiver comprising:

a receiver input coupled to an RF signal source;

a first mixer having a first input coupled to said receiver input and a second input coupled to a first reference signal having a first operating frequency, wherein said first operating frequency is variable between a minimum frequency value and a maximum frequency value;

a first bandpass filter constructed in the same substrate as said first mixer and coupled to an output of said first mixer; and

a second mixer having a first input coupled to an output of said first bandpass filter and a second input coupled to a second reference signal having a second operating frequency, wherein said second operating frequency is fixed.

98. The television receiver as set forth in claim 97 wherein said minimum frequency value is greater than an input cutoff frequency of an RF signal outputted from said RF signal source.

99. The television receiver as set forth in claim 98 wherein said first mixer subtractively mixes said RF signal and said first reference signal to thereby produce a first IF signal, wherein a selected carrier frequency in said RF signal appears at a first predetermined frequency in said first IF signal and said first predetermined frequency is greater than said selected carrier frequency.

100. The television receiver as set forth in claim 99 wherein said selected carrier frequency appears at said first predetermined frequency in an output passband signal of said bandpass filter.

101. The television receiver as set forth in claim 100 wherein said second mixer mixes said output passband signal and said second reference signal to thereby produce a second IF signal, wherein said selected carrier frequency appears in said second IF signal at a second predetermined frequency and said second predetermined frequency is less than said first predetermined frequency and said second operating frequency.

102. A method of processing a received RF signal, the method comprising the steps of:

mixing the RF signal with a first reference signal having a first operating frequency to thereby produce a first IF signal;

filtering the first IF signal in a first bandpass filter to produce an output passband signal having at least four channels; and

mixing the output passband signal with a second reference signal having a second operating frequency to thereby produce a second IF signal.

103. The method as set forth in claim 102 including the further step of filtering out of the RF signal all frequency components above an input cutoff frequency.

104. The method as set forth in claim 103 wherein the first operating frequency is greater than the input cutoff frequency.

105. The method as set forth in claim 104 wherein the step of mixing the RF signal with the first reference signal is a subtractive mixing of the RF signal and the first reference signal.

106. The method as see forth in claim 105 wherein the step of mixing the RF signal with the first reference signal is an up-conversion mixing, wherein a selected carrier frequency in the RF signal appears in the first IF signal at a first predetermined frequency and wherein the first predetermined frequency is higher than the selected carrier frequency.

107. The method as set forth in claim 106 wherein the first predetermined frequency appears in the output passband signal of the first bandpass filter.

108. A method of processing a received RF signal, the method comprising the steps of:

filtering all frequency components above an input cutoff frequency out of the received RF signal to thereby produce a first filtered signal;

amplifying the first filtered signal;

subtractively mixing the amplified first filtered signal with a first reference signal having a first operating frequency to thereby produce a first IF signal;

filtering the first IF signal in a bandpass filter to produce an output passband signal having at least four channels; and

mixing the output passband signal with a second reference signal having a second operating frequency to thereby produce a second IF signal.

109. The method as set forth in claim 108 wherein the first operating frequency is greater than the input cutoff frequency.

110. The method as set forth in claim 109 wherein the step of mixing the amplified first filtered signal with the first reference signal is an up-conversion mixing, wherein a selected carrier signal in said received RF signal appears in the first IF signal at a first predetermined frequency and wherein said first predetermined frequency is higher than the selected carrier frequency.

111. The method as set forth in claim 110 wherein the selected carrier signal appears in the output passband signal at the first predetermined frequency.

112. The method as set forth in claim 108 wherein the step of mixing the output passband signal with the second reference signal is a down conversion mixing, wherein a selected carrier signal appearing at a first predetermined frequency in the output passband signal appears in the second IF signal at a second predetermined frequency and wherein said second predetermined frequency is lower than said first predetermined frequency.

113. The method as set forth in claim 108 including the further step of filtering the second IF signal with a second bandpass filter.

114. The method as set forth in claim 113 wherein the second bandpass filter has a passband between 15 Megahertz and 21 Megahertz.

115. The method as set forth in claim 114 wherein the second bandpass filter is a Nyquist slope filter having a cutoff frequency of 20 Megahertz.

116. The method of extracting a single communications channel from a large number of such channels wherein each such channel has a defined frequency range, and wherein the large number of channels are communicated within an upper and a lower frequency boundary, the method comprising the steps of:

from an input signal containing all of the large number of channels removing all frequencies greater than the upper frequency boundary;

translating all of the channels contained within the input signal to a translated frequency range such that a desired single channel to be extracted from the input signal is positioned centrally within the translated frequency range, the translated frequency range being positioned at frequencies higher than the upper frequency boundary;

removing from the translated input signal all channels extending from the center of the translated frequency range four channels or more in each frequency direction;

translating the remaining channels within the input signal to a second translated frequency range, such that the desired single channel to be extracted from the input signal is positioned centrally within the second translated frequency range having a low end frequency boundary defined as high enough not to cause phase distortion in any subsequent filtering and a high end frequency boundary defined as a frequency beyond which a filter with proper bandwidth, noise and distortion can be integrated in a substrate; and

removal of all remaining frequencies which are not part of the desired single channel.

117. The method set forth in claim 116 wherein the last-mentioned removal step includes a receiver attenuation characteristic such that the relative amplitude of low and high frequencies within the desired single channel are corrected for vestigial sideband demodulation.

118. The method set forth in claim 116 wherein the low end and high end boundaries of the second translated frequency range are defined by the implementation of an integrated circuit continuous time filter capable of achieving single channel TV signal extraction and receiver attenuation characteristics.

120. A television receiver comprising:

a receiver input for receiving an RF signal;

an input filter coupled to said receiver input and operating to remove all frequency components in said RF signal above an input cutoff frequency to produce a filtered RF signal;

a first reference signal having a first operating frequency;

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

a second reference signal having a second operating frequency; and

a second mixer having a first input coupled to an output of said first mixer and a second input coupled to said second reference signal, wherein said second mixer is an image rejection mixer.

121. The television receiver of claim 120 wherein said first operating frequency is variable between a minimum frequency value and a maximum frequency value.

122. The television receiver of claim 121 wherein said minimum frequency value is greater than said input cutoff frequency.

123. The television receiver of claim 120 wherein said first mixer subtractively mixes said first reference signal and said filtered RF signal to thereby generate a first IF signal at said first mixer output.

124. The television receiver of claim 120 wherein said second mixer mixes a first IF signal from said first mixer and said second reference signal to generate a second IF signal and wherein said second mixer rejects an image signal of said second reference signal from said second IF signal.

125. The television receiver of claim 120 wherein said second mixer mixes a first IF signal from said first mixer and said second reference signal to generate a second IF signal and wherein said second mixer rejects an image signal of said first IF signal from said second IF signal.

126. The television receiver of claim 120 wherein said first mixer generates a first IF signal and wherein a selected carrier frequency in said RF signal appears at a first predetermined frequency in said first IF signal.

127. The television receiver of claim 126 wherein said second mixer generates a second IF signal and wherein said selected carrier frequency in said RF signal appears at a second predetermined frequency in said second IF signal.

128. The television receiver of claim 120 wherein said first mixer and said second mixer are physically located on the same integrated circuit substrate.