Reception mode control in radio receivers for receiving both VSB and QAM digital television signals

• US 6,137,545 A
• Filed: 08/16/1999
• Issued: 10/24/2000
• Est. Priority Date: 06/28/1994
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Limberg, Allen LeRoy, Patel, Chandrakant B.
• Primary Examiner(s): Kostak, Victor R.
• Application Number:
  US09/375,213
• Time in Patent Office: 435 Days
• Field of Search: 348/725, 348/726, 348/558, 348/423, 348/470, 348/720, 348/21, 348/607, 348/611, 75/251, 75/350, 75/261, 75/345, 75/346
• US Class Current: 348/726
• CPC Class Codes: H03D 1/24 for demodulation of signals wherein one sideband or the carrier has been wholly or partially suppressed receiver circuits H04B1/302
• CPC Class Codes: H03D 5/00 Circuits for demodulating amplitude-modulated or angle-modulated oscillations at will H03D9/00, H03D11/00 take precedence
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04H 20/95 characterised by a specific format, e.g. an encoded audio stream
• CPC Class Codes: H04H 40/27 specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95
• CPC Class Codes: H04L 1/0054 Maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms
• CPC Class Codes: H04L 2027/0028 at passband only
• CPC Class Codes: H04L 2027/0055 single phase
• CPC Class Codes: H04L 2027/0057 quadrature phase
• CPC Class Codes: H04L 2027/0067 Phase error detectors
• CPC Class Codes: H04L 2027/0087 Out-of-band signals, (e.g. pilots)
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04L 27/0012 arrangements for identifying the type of modulation
• CPC Class Codes: H04L 27/063 Superheterodyne receivers
• CPC Class Codes: H04L 27/066 Carrier recovery circuits H04L27/2271 takes precedence
• CPC Class Codes: H04L 27/38 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04L 27/3827 in which the carrier is recovered using only the demodulated baseband signals
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• 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 5/46 : for receiving on more than one standard at will deflecting circuits of multi-standard receivers H04N3/27
• CPC Class Codes: H04N 7/08 : Systems for the simultaneous or sequential transmission of more than one television signal, e.g. additional information signals, the signals occupying wholly or partially the same frequency band , e.g. by time division H04N7/007 takes precedence

Abstract

A radio receiver uses the same tuner for receiving a selected wideband digital signal of at least a few megahertz bandwidth, such as a digital television (DTV) signal, irrespective of whether it is a quadrature-amplitude-modulation (QAM) or a vestigial sideband (VSB) signal accompanied by an unmodulated pilot carrier signal; and a second transmission standard specifies quadrature amplitude modulation. It is determined at the receiver which of respective modulation formats specified for the various transmission standards is employed for transmitting the wideband digital signal being received. The wideband digital signal is demodulated to produce a demodulated signal, demodulation be done according to a demodulation format suitable for demodulating the modulation format determined to be employed for transmitting the wideband digital signal. The demodulated signal produced by demodulating the wideband digital signal according to this demodulation format is further processed according to the transmission standard determined at the receiver to have been employed for transmitting the wideband digital signal.

Claims

1. A method of receiving and processing a wideband digital signal, said wideband digital signal transmitted in accordance with any one of a plurality of various transmission standards including at least first and second transmission standards, said first transmission standard specifying vestigial sideband amplitude modulation according to a multi-level symbol code, and said second transmission standard specifying quadrature amplitude modulation, said method being carried out in a receiver for said wideband digital signal and comprising the steps of:

receiving said wideband digital signal at said receiver;

determining at said receiver which of respective modulation formats specified for said various transmission standards is employed for transmitting said wideband digital signal, to supply a determination of the transmission standard employed for transmitting said wideband digital signal;

demodulating said wideband digital signal according to a demodulation format suitable for demodulating the modulation format determined to be employed for transmitting said wideband digital signal, to produce a demodulated signal; and

further processing said demodulated signal produced by demodulating said wideband digital signal according to a demodulation format suitable for demodulating the modulation format that is determined at said receiver to be employed for transmitting said wideband digital signal.

2. The method of claim 1, wherein the step of receiving said wideband digital signal at said receiver involves reception from at least two of various media including terrestrial radio transmission, satellite radio transmission and cable transmission.

3. The method of claim 1, wherein said various transmission standards employ a plurality of coding formats, with different coding formats being specified in ones of said various transmission standards, said first transmission standard prescribing Reed-Solomon error-correction coding of randomized data followed by trellis coding, said method further comprising the steps of:

selecting from said plurality of coding formats a coding format specified in the transmission standard for said wideband digital signal, as determined from the modulation format that said wideband digital signal is determined to have been transmitted by; and

decoding said demodulated signal in accordance with a decoding format appropriate for said selected coding format, to produce a demodulated and decoded signal, said step of decoding being performed by the following substeps when said wideband digital signal is determined to have been transmitted by said first transmission standard;

trellis decoding said demodulated signal according to a trellis decoding format suitable for decoding the trellis coding format specified by said first transmission standard, thereby to generate first trellis decoding results,

subjecting said first trellis decoding results to a Reed-Solomon error-correction decoding procedure suitable for decoding the Reed-Solomon error-correction coding format specified by said first transmission standard, thereby to recover randomized data as first Reed-Solomon error-correction decoding results, and

de-randomizing said first Reed-Solomon error-correction decoding results in a de-randomizing procedure suitable for de-randomizing data randomized as specified by said first transmission standard, thereby to recover a transmitted datastream.

4. The method of claim 3, wherein said various transmission standards employ a plurality of coding formats, with different coding formats being specified in ones of said various transmission standards, said second transmission standard prescribing a coding format including Reed-Solomon error-correction coding of randomized data followed by trellis coding, said step of decoding being performed by the following substeps when said wideband digital signal is determined to have been transmitted by said second transmission standard:

trellis decoding said demodulated signal according to a trellis decoding format suitable for decoding the trellis coding format specified by said second transmission standard, thereby to generate second trellis decoding results,

subjecting said second trellis decoding results to a Reed-Solomon error-correction decoding procedure suitable for decoding the Reed-Solomon error-correction coding format specified by said second transmission standard, thereby to recover randomized data as second Reed-Solomon error-correction decoding results, and

de-randomizing said second Reed-Solomon error-correction decoding results in a de-randomizing procedure suitable for de-randomizing data randomized as specified by said second transmission standard, thereby to recover a transmitted datastream.

5. The method of claim 1, wherein said various transmission standards employ a plurality of coding formats, with different coding formats being specified in ones of said various transmission standards, said second transmission standard prescribing a coding format including Reed-Solomon error-correction coding of randomized data followed by trellis coding, said step of decoding being performed by the following substeps when said wideband digital signal is determined to have been transmitted by said second transmission standard:

trellis decoding said demodulated signal according to a trellis decoding format suitable for decoding the trellis coding format specified by said second transmission standard, thereby to generate trellis decoding results,

subjecting said trellis decoding results to a Reed-Solomon error-correction decoding procedure suitable for decoding the Reed-Solomon error-correction coding format specified by said second transmission standard, thereby to recover randomized data as Reed-Solomon error-correction decoding results, and

de-randomizing said Reed-Solomon error-correction decoding results in a de-randomizing procedure suitable for de-randomizing data randomized as specified by said second transmission standard, thereby to recover a transmitted datastream.

6. A method of receiving and processing a wideband digital signal, said wideband digital signal transmitted in accordance with any one of a plurality of various transmission standards including at least first and second transmission standards, said first transmission standard specifying vestigial sideband amplitude modulation according to a multi-level symbol code, in which said first transmission standard said vestigial sideband amplitude modulation is accompanied by an unmodulated pilot carrier signal, and said second transmission standard specifying quadrature amplitude modulation, said method being carried out in a receiver for said wideband digital signal and comprising the steps of:

receiving said wideband digital signal at said receiver;

determining from said wideband digital signal, as received at said receiver, which of respective modulation formats specified for said various transmission standards is employed for transmitting said wideband digital signal, to supply a determination of the transmission standard employed for transmitting said wideband digital signal;

demodulating said wideband digital signal according to a demodulation format suitable for demodulating the modulation format determined to be employed for transmitting said wideband digital signal, to produce a demodulated signal;

selecting for further processing said demodulated signal produced by demodulating said wideband digital signal according to a demodulation format suitable for demodulating the modulation format employed for transmitting said wideband digital signal, said selecting being made responsive to said determination of the modulation format employed for transmitting said wideband digital signal; and

further processing said demodulated signal so selected.

7. The method of claim 6, wherein the step of receiving said wideband digital signal at said receiver involves reception from at least two of various media including terrestrial radio transmission, satellite radio transmission and cable transmission.

8. The method of claim 6, wherein said step of determining from said wideband digital signal which of respective modulation formats specified for said various transmission standards is employed for transmitting said wideband digital signal comprises:

detecting when the wideband digital signal is transmitted by a modulation format specified by one of said transmission standards other than the second, to generate a determination that that one of said various transmission standards is employed for transmitting said wideband digital signal, and

otherwise generating a determination that said second transmission standard is employed for transmitting said wideband digital signal.

9. The method of claim 8, wherein said substep of detecting when said wideband digital signal is transmitted by a modulation format specified by the first of said transmission standards includes:

synchronously detecting the currently received wideband digital signal at the carrier frequency of a transmission per said first transmission standard; and

sensing the presence of a direct component indicative of pilot carrier at that carrier frequency to generate a determination that said second transmission standard is employed for transmitting said wideband digital signal.

10. The method of claim 9, wherein said various transmission standards employ a plurality of coding formats, with different coding formats being specified in ones of said various transmission standards, said first transmission standard prescribing Reed-Solomon error-correction coding of randomized data followed by trellis coding, said method further comprising the steps of:

selecting from said plurality of coding formats a coding format specified in the transmission standard for said wideband digital signal, as determined from the modulation format that said wideband digital signal is determined to have been transmitted by; and

decoding said demodulated signal in accordance with a decoding format appropriate for said selected coding format, to produce a demodulated and decoded signal, said step of decoding being performed by the following substeps when said wideband digital signal is determined to have been transmitted by said first transmission standard;

trellis decoding said demodulated signal according to a trellis decoding format suitable for decoding the trellis coding format specified by said first transmission standard, thereby to generate first trellis decoding results,

subjecting said first trellis decoding results to a Reed-Solomon error-correction decoding procedure suitable for decoding the Reed-Solomon error-correction coding format specified by said first transmission standard, thereby to recover randomized data as first Reed-Solomon error-correction decoding results, and

de-randomizing said first Reed-Solomon error-correction decoding results in a de-randomizing procedure suitable for de-randomizing data randomized as specified by said first transmission standard, thereby to recover a transmitted datastream.

11. The method of claim 10, wherein said second transmission standard employs a coding format including Reed-Solomon error-correction coding of randomized data followed by trellis coding, said step of decoding being performed by the following substeps when said wideband digital signal is determined to have been transmitted by said second transmission standard:

trellis decoding said demodulated signal according to a trellis decoding format suitable for decoding the trellis coding format specified by said second transmission standard, thereby to generate second trellis decoding results,

subjecting said second trellis decoding results to a Reed-Solomon error-correction decoding procedure suitable for decoding the Reed-Solomon error-correction coding format specified by said second transmission standard, thereby to recover randomized data as second Reed-Solomon error-correction decoding results, and

de-randomizing said second Reed-Solomon error-correction decoding results in a de-randomizing procedure suitable for de-randomizing data randomized as specified by said second transmission standard, thereby to recover a transmitted datastream.

12. The method of claim 9, wherein said various transmission standards employ a plurality of coding formats, with different coding formats being specified in ones of said various transmission standards, said second transmission standard prescribing a coding format including Reed-Solomon error-correction coding of randomized data followed by trellis coding, said step of decoding being performed by the following substeps when said wideband digital signal is determined to have been transmitted by said second transmission standard:

trellis decoding said demodulated signal according to a trellis decoding format suitable for decoding the trellis coding format specified by said second transmission standard, thereby to generate trellis decoding results,

subjecting said trellis decoding results to a Reed-Solomon error-correction decoding procedure suitable for decoding the Reed-Solomon error-correction coding format specified by said second transmission standard, thereby to recover randomized data as Reed-Solomon error-correction decoding results, and

de-randomizing said Reed-Solomon error-correction decoding results in a de-randomizing procedure suitable for de-randomizing data randomized as specified by said second transmission standard, thereby to recover a transmitted datastream.

13. A method of receiving and processing a wideband digital signal, said wideband digital signal transmitted in accordance with any one of a plurality of various transmission standards including at least first and second transmission standards, said first transmission standard specifying vestigial sideband amplitude modulation according to a multi-level symbol code, in which said first transmission standard said vestigial sideband amplitude modulation is accompanied by an unmodulated pilot carrier signal, and said second transmission standard specifying quadrature amplitude modulation, said method being carried out in a receiver for said wideband digital signal and comprising the steps of:

receiving said wideband digital signal at said receiver;

demodulating said wideband digital signal according to each of said demodulation formats to produce respective demodulated signals;

determining from said wideband digital signal, as received at said receiver, which of respective modulation formats specified for said various transmission standards is employed for transmitting said wideband digital signal, to supply a determination of the transmission standard employed for transmitting said wideband digital signal; and

selecting, for further processing, the one of said respective demodulated signals corresponding to the modulation format employed for transmitting said wideband digital signal.

14. The method of claim 13, wherein the step of receiving said wideband digital signal at said receiver involves reception from at least two of various media including terrestrial radio transmission, satellite radio transmission and cable transmission.

15. The method of claim 13, wherein said step of determining from said wideband digital signal which of respective modulation formats specified for said various transmission standards is employed for transmitting said wideband digital signal comprises:

detecting when the wideband digital signal is transmitted by a modulation format specified by one of said transmission standards other than the second, to generate a determination that that one of said various transmission standards is employed for transmitting said wideband digital signal, and

otherwise generating a determination that said second transmission standard is employed for transmitting said wideband digital signal.

16. The method of claim 15, wherein said substep of detecting when said wideband digital signal is transmitted by a modulation format specified by the first of said transmission standards includes:

synchronously detecting the currently received wideband digital signal at the carrier frequency of a transmission per said first transmission standard; and

sensing the presence of a direct component indicative of pilot carrier at that carrier frequency to generate a determination that said second transmission standard is employed for transmitting said wideband digital signal.

17. The method of claim 16, wherein said various transmission standards employ a plurality of coding formats, with different coding formats being specified in ones of said various transmission standards, said first transmission standard prescribing Reed-Solomon error-correction coding of randomized data followed by trellis coding, said method further comprising the steps of:

selecting from said plurality of coding formats a coding format specified in the transmission standard for said wideband digital signal, as determined from the modulation format that said wideband digital signal is determined to have been transmitted by; and

decoding said demodulated signal in accordance with a decoding format appropriate for said selected coding format, to produce a demodulated and decoded signal, said step of decoding being performed by the following substeps when said wideband digital signal is determined to have been transmitted by said first transmission standard;

trellis decoding said demodulated signal according to a trellis decoding format suitable for decoding the trellis coding format specified by said first transmission standard, thereby to generate first trellis decoding results,

subjecting said first trellis decoding results to a Reed-Solomon error-correction decoding procedure suitable for decoding the Reed-Solomon error-correction coding format specified by said first transmission standard, thereby to recover randomized data as first Reed-Solomon error-correction decoding results, and

de-randomizing said first Reed-Solomon error-correction decoding results in a de-randomizing procedure suitable for de-randomizing data randomized as specified by said first transmission standard, thereby to recover a transmitted datastream.

18. The method of claim 17, wherein said second transmission standard employs a coding format including Reed-Solomon error-correction coding of randomized data followed by trellis coding, said step of decoding being performed by the following substeps when said wideband digital signal is determined to have been transmitted by said second transmission standard:

trellis decoding said demodulated signal according to a trellis decoding format suitable for decoding the trellis coding format specified by said second transmission standard, thereby to generate second trellis decoding results,

subjecting said second trellis decoding results to a Reed-Solomon error-correction decoding procedure suitable for decoding the Reed-Solomon error-correction coding format specified by said second transmission standard, thereby to recover randomized data as second Reed-Solomon error-correction decoding results, and

de-randomizing said second Reed-Solomon error-correction decoding results in a de-randomizing procedure suitable for de-randomizing data randomized as specified by said second transmission standard, thereby to recover a transmitted datastream.

19. The method of claim 16, wherein said various transmission standards employ a plurality of coding formats, with different coding formats being specified in ones of said various transmission standards, said second transmission standard prescribing a coding format including Reed-Solomon error-correction coding of randomized data followed by trellis coding, said step of decoding being performed by the following substeps when said wideband digital signal is determined to have been transmitted by said second transmission standard:

trellis decoding said demodulated signal according to a trellis decoding format suitable for decoding the trellis coding format specified by said second transmission standard, thereby to generate trellis decoding results,

subjecting said trellis decoding results to a Reed-Solomon error-correction decoding procedure suitable for decoding the Reed-Solomon error-correction coding format specified by said second transmission standard, thereby to recover randomized data as Reed-Solomon error-correction decoding results, and

de-randomizing said Reed-Solomon error-correction decoding results in a de-randomizing procedure suitable for de-randomizing data randomized as specified by said second transmission standard, thereby to recover a transmitted datastream.