Electronic component with integrated tuning device, allowing the decoding of digital terrestrial or cable television signals

• US 20040259512A1
• Filed: 04/06/2004
• Published: 12/23/2004
• Est. Priority Date: 04/11/2003
• Status: Active Grant

• Current Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Inventors: Busson, Pierre, Paille, Bruno, Jouffre, Pierre-Oliver
• Granted Patent: US 7,406,304 B2
• Time in Patent Office: Days
• US Class Current: 455/190.1
• CPC Class Codes: H03D 7/165 at least two frequency changers being located in different paths, e.g. in two paths with carriers in quadrature combined with amplitude demodulation H03D1/2245, combined with angle demodulation H03D3/007; N-path filters H03H19/002
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/6112 involving terrestrial transmission, e.g. DVB-T
• 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

Abstract

An integrated superheterodyne dual-conversion tuner upconverts a signal so as to place it outside a reception band, and then downconverts the signal with a non-zero intermediate frequency. A first filter of the bulk acoustic wave type is positioned between the up and down conversion and is calibrated in such a way as to accurately determine its central frequency. A second filter of a microelectromechanical type receives the downconverted signal and is calibrated in such a way as to accurately determine its central frequency.

Claims

1. An electronic component, comprising:

an integrated circuit embodied on a monolithic substrate and comprising;

a superheterodyne type tuning module with non zero intermediate frequency dual upconversion then downconversion, possessing an input able to receive digital terrestrial or cable television analog signals composed of several channels,

a bulk acoustic wave type bandpass filter disposed between two frequency transposition stages of the tuning module and delivering a filtered analog signal containing the information conveyed by a desired channel and adjacent channels information,

a microelectromechanical type bandpass filter disposed downstream of a second frequency transposition stage and able to eliminate the adjacent channels information;

first means for determining the central frequency of the bulk acoustic wave filter, and

second means for determining the central frequency of the microelectromechanical filter.

2. The component according to claim 1, wherein the first means for determining comprise means in the absence of a signal at the input of a first transposition stage for varying beyond an upper limit of a frequency span of the channels the frequency of a calibration transposition signal applied to the first transposition stage, and detection means for determining for each value of the frequency of the calibration signal the power of the signal at the output of the bulk acoustic wave filter and to detect the maximum power, the central frequency of the bulk acoustic wave filter then being the frequency of the calibration signal corresponding to this maximum value of power.

3. The component according to claim 2, wherein the second means for determining comprises means able in the absence of any signal at the input of the second transposition stage for varying in the neighborhood of a predetermined reference intermediate frequency the frequency of a calibration transposition signal applied to the second transposition stage, and means for detecting that determines for each value of the frequency of the calibration signal the power of the signal at the output of the microelectromechanical filter and to detect the maximum power, the central frequency of the microelectromechanical filter then being the frequency of the calibration signal corresponding to this maximum value of power.

4. The component according to claim 3, wherein after the determination of the central frequency of the bulk acoustic wave filter the first frequency transposition stage is configured to receive a first transposition signal having a frequency equal either to the sum of the frequency of the desired channel and of the said central frequency of the bulk acoustic wave filter greater than the upper limit of the frequency span, or to the difference between the central frequency and the frequency of the desired channel, in that after the determination of the central frequency of the microelectromechanical filter the second frequency transposition stage is able to receive a second transposition signal having a frequency equal to the said central frequency of the bulk acoustic wave filter minus the central frequency of the microelectromechanical filter, and wherein the passband of the bulk acoustic wave filter is of the order of two to three times the frequency width of a channel, and wherein the passband of the microelectromechanical filter is of the order of the frequency width of a channel.

5. The component according to claim 4, wherein the passband of the bulk acoustic wave filter is of the order of 20 MHz, and in that the passband of the microelectromechanical filter is of the order of 8 MHz.

6. The component according to claim 1, wherein the component comprises a digital stage linked to the tuning module by an analog/digital conversion stage, and comprising a channel decoder circuit.

7. The component according to claim 6, wherein the digital stage incorporates the first and second means for determining.

8. The component according to claim 1, wherein the first means for determining and the second means for determining are embodied within one and the same hardware architecture.

9. The component of claim 1, wherein the component is a part within a digital terrestrial or cable television signal receiver.

10. The component according to claim 1, wherein the second means for determining comprises means able in the absence of any signal at the input of the second transposition stage for varying in the neighborhood of a predetermined reference intermediate frequency the frequency of a calibration transposition signal applied to the second transposition stage, and means for detecting that determines for each value of the frequency of the calibration signal the power of the signal at the output of the microelectromechanical filter and to detect the maximum power, the central frequency of the microelectromechanical filter then being the frequency of the calibration signal corresponding to this maximum value of power.

21. The circuit of claim 1 wherein the channels of the analog signal extend over a frequency span and wherein the upconversion device upconverts the received analog signal to a frequency that is higher than an upper limit of the frequency span.

11. A circuit, comprising:

an input receiving an analog signal including a plurality of channels;

an upconversion device to upconvert the received analog signal;

a first filter that filters the received analog signal and generates a filtered upconverted signal comprising information from a selected one of the channels and adjacent channel information;

a downconversion device to downconvert the filtered upconverted signal to an analog downconverted signal centered at a non-zero frequency;

a second filter that filters the analog downconverted signal and generates a filtered analog downconverted signal comprising information from the selected one of the channels and less of the adjacent channel information;

a digital-to-analog converter to convert the analog downconverted signal to a digital baseband signal; and

a third filter that filters the digital baseband signal and generates a filtered digital baseband signal comprising only information from the selected one of the channels.

12. The circuit of claim 11 wherein all of the recited components of the circuit are implemented on a single integrated circuit chip.

13. The circuit of claim 11 wherein the first filter is a bulk acoustic wave filter having, from a design perspective, a not accurately known center frequency.

14. The circuit of claim 13 further including a calibration circuit that determines the not accurately known center frequency of the bulk acoustic wave filter and configures the upconversion device to upconvert the received analog signal such that the selected one of the channels is placed at the determined center frequency.

15. The circuit of claim 14 wherein the calibration circuit comprises:

a power measurement circuit;

a first switch to disconnect the analog signal from the upconversion device;

a second switch to connect an output of the bulk acoustic wave filter to the power measurement device; and

a control circuit that varies a frequency transposition signal applied to the upconversion device and determines a frequency of the varying frequency transposition signal at which the power measurement device measures maximum power passing through the bulk acoustic wave filter, that determined frequency being the center frequency.

16. The circuit of claim 11 wherein the second filter is a microelectromechanical filter having, from a design perspective, a not accurately known center frequency.

17. The circuit of claim 16 further including a calibration circuit that determines the not accurately known center frequency of the microelectromechanical filter and configures the downconversion device to downconvert the filtered upconverted signal such that the selected one of the channels is placed at the determined center frequency.

18. The circuit of claim 17 wherein the calibration circuit comprises:

a power measurement circuit;

a first switch to disconnect the filtered upconverted signal from the downconversion device;

a second switch to connect an output of the microelectromechanical filter to the power measurement device; and

a control circuit that varies a frequency transposition signal applied to the upconversion device and determines a frequency of the varying frequency transposition signal at which the power measurement device measures maximum power passing through the microelectromechanical filter, that determined frequency being the center frequency.

19. The circuit of claim 11 wherein the analog signal is one of a digital terrestrial or cable television signal.

20. The circuit of claim 11 wherein the upconversion device and downconversion device comprises an intermediate frequency dual conversion tuner.

22. The circuit of claim 11 further including means for decoding the filtered digital baseband signal to deliver a stream of data packets corresponding to information in the selected one of the channels.

23. The circuit of claim 22 wherein all of the recited components of the circuit are implemented on a single integrated circuit chip and the first filter is connected to the single integrated circuit chip as an off-chip component.

24. The circuit of claim 11, wherein the circuit is included within a digital terrestrial or cable television signal receiver box.

25. The circuit of claim 11 wherein the first filter, from a design perspective, has a not accurately known first center frequency and wherein the second filter, from a design perspective, has a not accurately known second center frequency.

26. The circuit of claim 25 further including a calibration circuit that determines the not accurately known first and second center frequencies of the first and second filters, respectively, and configures the upconversion device to upconvert the received analog signal such that the selected one of the channels is placed at the determined first center frequency and configures the downconversion device to downconvert the filtered upconverted signal such that the selected one of the channels is placed at the determined second center frequency.

27. A circuit, comprising:

an input receiving an analog signal including a plurality of channels;

an upconversion device to upconvert the received analog signal;

a filter that filters the received analog signal and generates a filtered upconverted signal comprising information from a selected one of the channels and adjacent channel information, wherein the filter, from a design perspective, has a not accurately known center frequency; and

a calibration circuit that determines the not accurately known center frequency of the filter and configures the upconversion device to upconvert the received analog signal such that the selected one of the channels is placed at the determined center frequency.

28. The circuit of claim 27 wherein all of the recited components of the circuit are implemented on a single integrated circuit chip.

29. The circuit of claim 27 wherein the filter is a bulk acoustic wave filter.

30. The circuit of claim 27 wherein the calibration circuit comprises:

a power measurement circuit;

a first switch to disconnect the analog signal from the upconversion device;

a second switch to connect an output of the filter to the power measurement device; and

a control circuit that varies a frequency transposition signal applied to the upconversion device and determines a frequency of the varying frequency transposition signal at which the power measurement device measures maximum power passing through the filter, that determined frequency being the center frequency.

31. A circuit, comprising:

an input receiving an analog signal comprising information from a selected one of a plurality of channels and adjacent channel information;

a downconversion device to downconvert the analog signal to an analog downconverted signal centered at a non-zero frequency;

a filter that filters the analog downconverted signal and generates a filtered analog downconverted signal comprising information from the selected one of the channels and less of the adjacent channel information, wherein the filter, from a design perspective, has a not accurately known center frequency; and

a calibration circuit that determines the not accurately known center frequency of the filter and configures the downconversion device to downconvert the filtered analog signal such that the selected one of the channels is placed at the determined center frequency.

32. The circuit of claim 31 wherein all of the recited components of the circuit are implemented on a single integrated circuit chip.

33. The circuit of claim 31 wherein the filter is a microelectromechanical filter.

34. The circuit of claim 31 wherein the calibration circuit comprises:

a power measurement circuit;

a first switch to disconnect the analog signal from the downconversion device;

a second switch to connect an output of the filter to the power measurement device; and

a control circuit that varies a frequency transposition signal applied to the upconversion device and determines a frequency of the varying frequency transposition signal at which the power measurement device measures maximum power passing through the filter, that determined frequency being the center frequency.

35. A method for processing an analog signal including a plurality of channels;

upconverting the received analog signal;

first filtering the upconverted received analog signal to generate a filtered upconverted signal comprising information from a selected one of the channels and adjacent channel information;

downconverting the filtered upconverted signal to an analog downconverted signal centered at a non-zero frequency;

second filtering the analog downconverted signal to generate a filtered analog downconverted signal comprising information from the selected one of the channels and less of the adjacent channel information;

converting the analog downconverted signal to a digital baseband signal; and

third filtering the digital baseband signal to generate a filtered digital baseband signal comprising only information from the selected one of the channels.

36. The method of claim 35 wherein first filtering comprises filtering with a filter that, from a design perspective, does not have an accurately known center frequency, the method further comprising:

determining the not accurately known center frequency of the filter; and

configuring upconverting to upconvert the received analog signal such that the selected one of the channels is placed at the determined center frequency.

37. The method of claim 36 wherein determining comprises:

disconnecting the analog signal from being upconverted;

connecting an output of the first filter to a power measurement device;

varying a frequency transposition signal applied to effectuate upconverting; and

determining a frequency of the varying frequency transposition signal at which the power measurement device measures maximum power passing through the first filter, that determined frequency being the center frequency.

38. The method of claim 35 wherein second filtering comprises filtering with a filter that, from a design perspective, does not have an accurately known center frequency, the method further comprising:

determining the not accurately known center frequency of the filter; and

configuring downconverting to downconvert the filtered analog signal such that the selected one of the channels is placed at the determined center frequency.

39. The method of claim 38 wherein determining comprises:

disconnecting the filtered analog signal from being downconverted;

connecting an output of the second filter to a power measurement device;

varying a frequency transposition signal applied to effectuate downconverting; and

determining a frequency of the varying frequency transposition signal at which the power measurement device measures maximum power passing through the second filter, that determined frequency being the center frequency.

40. The method of claim 35 wherein the channels of the analog signal extend over a frequency span and wherein upconverting upconverts the received analog signal to a frequency that is higher than an upper limit of the frequency span.

41. The method of claim 35 further including decoding the filtered digital baseband signal to deliver a stream of data packets corresponding to information in the selected one of the channels.

42. The method of claim 35 wherein first filtering comprises bandpass filtering with a pass band of at least two times a frequency width of a channel in the analog signal.

43. The method of claim 35 wherein second filtering comprises low pass filtering with an upper cut-off frequency slightly greater than a frequency halfwidth of a channel in the analog signal.

44. The method of claim 35 wherein third filtering comprises low pass filtering with an upper cut-off frequency substantially equal to a frequency halfwidth of a channel in the analog signal.

45. A method for processing an analog signal including a plurality of channels;

upconverting the received analog signal;

filtering the upconverted received analog signal to generate a filtered upconverted signal comprising information from a selected one of the channels and adjacent channel information, wherein filtering comprises filtering with a filter that, from a design perspective, does not have an accurately known center frequency;

downconverting the filtered upconverted signal to a downconverted signal at a non-zero frequency;

determining the not accurately known center frequency of the filter;

configuring upconverting to upconvert the received analog signal such that the selected one of the channels is placed at the determined center frequency.

46. The method of claim 45 wherein determining comprises:

disconnecting the analog signal from being upconverted;

connecting an output of the filter to a power measurement device;

varying a frequency transposition signal applied to effectuate upconverting; and

determining a frequency of the varying frequency transposition signal at which the power measurement device measures maximum power passing through the filter, that determined frequency being the center frequency.