JP2000224556A - Network interface module and reception tuner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a network interface module with a simplified configuration and a reception tuner used therefor. SOLUTION: The network interface module to be arranged at the side of a house for connecting a CATV(cable television) station to a house side terminal is provided with a QPSK tuner 8 for receiving a data signal which is orthogonally phase-shifted and modulated(QPSK) among a downstream signal group transmitted from the CATV station. A circuit group for the nonusage band of a reception signal is omitted in the tuner 8 and, besides, a circuit part for selecting stations is shared in the circuit group for a VHF band(low frequency band) and a UHF band(high frequency band) to be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitably used for a cable modem for CATV (abbreviation of cable television) or an STB (abbreviation of set-top box) used by being mounted on a television receiver. The present invention relates to an NIM (abbreviation of a network interface module) and a receiving tuner, and more particularly, to an NIM and a receiving tuner having an improved circuit configuration.

[0002]

2. Description of the Related Art CATV operators are trying to increase the number of channels,
In order to provide a broadband data communication service using an empty channel, a home service line is a coaxial cable, and an HFC (Hybr
id Fiber Coax). Thus, for example, by using 64-level QAM (quadrature phase modulation), a high-speed data line with a bandwidth of 6 MHz and a transmission speed of 30 Mbit / sec can be created.
An NIM is mounted in such a CATV cable modem or STB for communication connection between a cable network and a television set or an information terminal device at home.

FIG. 3 is a block diagram of a conventional STB applied to the embodiment of the present invention.

FIG. 3 shows a conventional STB 40A, and a STB 40 applied to the embodiment of the present invention. In the figure, the STB 40A (40) is connected to a CATV station (not shown) through a cable line (not shown) and the STB.
B includes an input terminal 100 for communication connection.

A signal transmitted from an input terminal 100 to a CATV station via a cable line is called an upstream signal,
The signal transmitted from the V station to the input terminal 100 via the cable line is called a downlink signal. In CATV, for example, the upstream signal is operated at 5-42 MHz, and the downstream signal is operated at 5 MHz.
Operated at 4-860 MHz.

The STB 40A includes a NIM 1, a transport decoder 15 for extracting video and audio signals from a bit stream, an NPEG 2 decoder 16, a multiplexer 17, an RF (short for high frequency) modulator 18, a CPU 1
9. QPSK (quadrature phase shift keying: quadrature p)
QPSK modulator 2 for abbreviation of hase shift keying)
0, a power amplifier 21 and an output terminal 23.

The NIM 1 has an input terminal 100, an HPF (short for high-pass filter) 3, an LPF (short for low-pass filter) 4, a directional coupler 5, a digital tuner 6, an analog tuner 7, a QPSK tuner 8, and a digital SAW filter 9. , NTSC (national television system com
abbreviation of mittee) demodulator 10, QPSK demodulator 11, down converter 12, ADC (abbreviation of analog / digital converter) 13, QAM demodulator 14, two distributor 22, data terminal 26, both side adjacent trap circuit 32, analog SA
W filter 33 and IF (short for intermediate frequency) amplifier 3
4 inclusive.

The upstream signal is amplified by a power amplifier 21 as a data signal subjected to quadrature phase shift modulation by a QPSK modulator 22 and then applied to a data terminal 26. The data signal supplied to the data terminal 26 is sent to the cable line via the LPF 4 which is an upstream circuit and the input terminal 100.

Each of tuners 6 to 8 is 470 to 86
UHF band (B3 band) receiving 0 MHz, 17
VHF High band (B2 band) receiving 0 MHz to 470 MHz, V receiving 54 to 170 MHz
It is divided into an HF Low band (B1 band) and includes a receiving circuit for each band. However, band division is not specified here.

The downstream signal is an IF that passes the downstream signal while operating to cut off the upstream signal with the input terminal 100.
After passing through the HPF 3 which is a filter, the directional coupler 5 distributes and supplies the signals to the tuner 6 and the two distributors 22. The downstream signal provided to the splitter 22 is divided into the analog tuner 7 for receiving the analog signal and the QPSK.
The modulated signal is supplied to a QPSK tuner 8 for signal reception.

Recent CATV signal types include an upstream signal and a downstream signal modulated according to QPSK, and an analog NTTV signal.
It is divided into an SC video signal and a digital QAM video signal. The CATV signal receiving STB 40A shown in FIG. 3 transmits and receives these signals and performs bidirectional processing. QP
The SK method is a type of data signal (digital signal) modulation method, and changes the phase of a carrier wave according to a digital signal sequence.

The analog NTSC video signal is converted into a digital QA by an analog video signal receiving circuit (circuits 7 to 10).
The M video signal is output to a QAM signal receiving circuit (circuits 6, 9, 12,
13, 14, 15 and 16). next,
The data signal modulated according to QPSK, which is a downstream signal, is processed by a QPSK signal receiving circuit (circuits 8 and 11),
The data signal modulated according to the uplink QPSK is QP
It is processed by the SK signal transmission circuit (circuits 20 and 21).

First, NTSC which is a downstream analog signal
The video signal passes through the input terminal 100, the HPF 3, the directional coupler 5, and the two-way distributor 22, and is then supplied to the analog tuner 7, where it is switched to an analog channel (channel for analog broadcast reception) whose channel selection is desired. The signal is converted into a corresponding IF signal, and is passed through an adjacent trap circuit 32, an IF amplifier 34, and an analog SAW filter 33 on both sides.
The C demodulator 10 converts the video signal and the audio signal into a composite signal CP1 and outputs the composite signal CP1 to the multiplexer 17.

On the other hand, the QAM-modulated digital signal passes through a directional coupler 5 and is converted by a digital tuner 6 into an IF signal corresponding to a digital channel (digital broadcast receiving channel) desired to be selected. Digital SAW
After being converted to a low-frequency IF signal by the down converter 12 via the filter 9, the signal is converted to an 8-bit or 10-bit digital signal by the ADC 13.

This digital signal is subjected to I and Q demodulation by a QAM demodulator 14 and error-corrected, and then output to a transport decoder 15 as a serial bit stream.

The transport decoder 15 extracts the video and audio signals composed of the input serial bit stream and outputs them to the MPEG2 decoder 16. The MPEG2 decoder 16 extends the band of the input video and audio signals and outputs the resultant to the multiplexer 17 as an analog composite signal CP2.

The multiplexer 17 outputs one of the two composite signals CP1 and CP2 to C
The signal is selected and output to the RF modulator 18 according to the instruction of the PU 19. In the RF modulator 18, the applied composite signal is modulated into a TV (abbreviation for television) signal of a desired channel, and is output from the output terminal 23 to the TV.
It is output to an antenna input terminal (not shown) of the receiver.

Next, for communication between the center side, which is a CATV station, and the STB 40A on the subscriber side, signals modulated in accordance with the QPSK method are used for uplink signals and downlink signals. First, a QPSK tuner for a signal modulated according to the QPSK scheme after a data signal modulated according to the downstream QPSK passes through the input terminal 100, the HPF 3, the directional coupler 5, and the splitter 22.
Tuned by tuner 8, the selected data signal is Q
Q for demodulating a signal modulated according to the PSK scheme
Demodulated by the PSK demodulator 11 and provided to the CPU 19.

The upstream data signal such as billing information is sent to the CPU 1
9 to modulate the signal according to the QPSK method
The signal is applied to a K modulator 20, where it is modulated, amplified by a power amplifier 21, and then transmitted from an input terminal 100 to a cable line via an LPF 4.

FIG. 4 is a block diagram of the conventional QPSK tuner 8A shown in FIG. In the figure, a conventional QPSK tuner 8A includes an input terminal 1, on the side of a two-way divider 22, an HPF (IF filter) 2 having an attenuation band of 5 to 46 MHz and a pass band of 54 MHz, a UHF, VHF input circuit and a switching circuit. Block B30, Block B4 Including High Frequency Amplifier and High Frequency Amplified Output Tuning Circuit
0, block B5 including local oscillation circuit and mixing circuit
0, intermediate frequency amplification output circuit 60, intermediate frequency amplifier 7
0, PLL (Phase Locked Loop) tuning circuit 13
1. PLL tuning terminal 12 related to PLL tuning circuit 131
A, PLL power supply terminal 12B, and intermediate frequency output terminal 2
30.

The blocks B30 to B50 correspond to the aforementioned B1.
To B3 band. The receiving circuit for each band includes the input switching circuits 31A to 31C of the block B30, the high-frequency amplification input tuning circuits 32A to 32C, the high-frequency amplifiers 41A to 41C whose gain is controlled in the block B40, and the high-frequency amplification output. Block B5 related to each of the tuning circuits 42A to 42C and the PLL tuning circuit 131
0, and each of the first local oscillation circuits 52A to 52C which are balanced local oscillation circuits.

The signal output from each receiving circuit is amplified to a predetermined level via an intermediate frequency amplifier circuit 60 and an intermediate frequency amplifier 70, and then output from an output terminal 230.

In FIG. 1, a downstream signal modulated according to the QPSK system passes through an HPF (IF filter) 2 and is provided to input switching circuits 31A to 31C. Only the receiving circuit corresponding to the operating frequency of (1) operates, and the other receiving circuits do not operate. The operation of each receiving circuit is common.

Next, an operation state of the receiving circuit of each band will be described. The downstream signal modulated according to the QPSK is received and passed through the input switching circuits 31A to 31C and the high frequency amplification input tuning circuits 32A to 32C.
The signals are amplified by 1A to 41C, and are derived as reception signals via high frequency amplification output tuning circuits 42A to 42C.

Thereafter, the received signals are supplied to the mixing circuits 51A to 51A.
The signal is converted into an intermediate frequency signal by C and local oscillation circuits 52A to 52C, and output from output terminal 230 via intermediate frequency amplifier circuit 60 and intermediate frequency amplifier 70.

[0026]

SUMMARY OF THE INVENTION STB for CATV
Alternatively, since a cable modem is required to be downsized, the NIM mounted thereon is also required to be downsized as an RF module.

However, if the conventional NIM shown in FIGS. 3 and 4 is modularized as it is, the module becomes large, and the STB or the cable modem on which the NIM is mounted is also reduced in size.

It is therefore an object of the present invention to provide a network interface module and a receiving tuner whose configurations are simplified and whose size is reduced.

[0029]

According to a first aspect of the present invention, there is provided a network interface module for transmitting and receiving signals to and from a CATV (abbreviated as cable television) station via a cable line, and has the following features. .

That is, an upstream signal transmitting unit for transmitting an upstream data signal to the CATV station to the cable line, and a downstream signal group including one or more types of signals from the CATV station while blocking the upstream data signal. And a receiving circuit unit for receiving the introduced downlink signal group.

The receiving circuit section has at least a tuner for receiving a predetermined signal modulated according to a predetermined modulation scheme in the downlink signal group. The tuner receives the modulated predetermined signal and extracts a first frequency band signal, and receives the modulated predetermined signal and outputs a second signal.
A filter converter for extracting the frequency band signal while converting the signal into the first frequency band signal, and a first frequency band signal output from each of the filter unit and the filter converter; And a signal conversion unit that converts the signal into a signal and outputs the signal.

[0032] In the reception band of the predetermined signal, bands other than the first and second frequency bands are unused bands.

According to the first aspect of the present invention, since a component for an unused band for a predetermined signal is omitted in the tuner, the size of the tuner can be reduced and the configuration of the network interface module in which the tuner is mounted can be reduced. Simplification is achieved.

Further, in the components for the first and second frequency bands that are used for the predetermined signal in the tuner, the signal converter is shared between the two bands, so that the tuner can be further reduced in size. In addition, the configuration of the network interface module equipped with the tuner is simplified.

A network interface module according to a second aspect has the following features in the network interface module according to the first aspect.

That is, the predetermined signal is a data signal, and the predetermined modulation method is a quadrature phase shift keying method in which the phase of a carrier of the data signal is changed according to a digital signal sequence indicating the data signal.

According to the second aspect, the data signal modulated according to the quadrature phase shift keying method among the downlink signals received via the cable line can be received by applying the above-described tuner. Therefore, the tuner for receiving the data signal can be reduced in size as compared with the related art, and the configuration of the network interface module to which the tuner is applied can be simplified.

According to a third aspect of the present invention, in the network interface module according to the first or second aspect, the signal converter has the following features.

That is, the signal conversion unit oscillates and outputs an oscillation at a frequency according to the level of the tuning signal based on the information of the desired reception channel, and mixes the input first frequency band signal with the oscillation signal output from the oscillating unit. A mixing unit for converting the signal into an intermediate frequency signal corresponding to the reception channel.

According to a fourth aspect of the present invention, a voltage controlled oscillation circuit is applied to the oscillating section of the third aspect of the present invention.

According to the third or fourth aspect, the reception frequency band of the tuner is configured to be received only in the first and second frequency bands, so that the reception range becomes narrower than in the past, and The appearance of phase noise in the received signal due to the influence of the oscillated signal can be suppressed. Therefore, the reception quality is improved.

According to the network interface module of the first to fourth aspects, the configuration is simplified, so that it is possible to reduce power consumption and cost.

The receiving tuner according to the fifth aspect is characterized in that
A receiving tuner for receiving a predetermined signal modulated according to a predetermined modulation scheme transmitted from a TV station, comprising: a filter unit for receiving a modulated predetermined signal and extracting a first frequency band signal; A filter conversion unit that receives the predetermined signal and converts the second frequency band signal into a first frequency band signal while extracting the first frequency band signal; and a first frequency band signal output from each of the filter unit and the filter conversion unit. A signal conversion unit for converting the signal into an intermediate frequency signal corresponding to a desired reception channel and outputting the intermediate frequency signal, wherein a band other than the first and second frequency bands in the reception frequency band of the predetermined signal is an unused band. And

According to the fifth aspect, in the receiving tuner, a component for an unused band with respect to a predetermined signal is omitted, so that the tuner can be downsized and the network interface module in which the tuner is mounted can be reduced. The configuration is simplified.

Further, in the components for the first and second wavenumber bands in use for the predetermined signal in the receiving tuner, the signal converter is shared between the two bands. The size and the configuration of the network interface module on which the tuner is mounted are simplified.

A receiving tuner according to a sixth aspect further has the following features in the receiving tuner according to the fifth aspect.

That is, the predetermined signal is a data signal, and the predetermined modulation method is a quadrature phase shift keying method in which the phase of the carrier of the data signal is changed according to a digital signal sequence indicating the data signal.

According to the sixth aspect, it is possible to receive a data signal modulated by the receiving tuner according to the quadrature phase shift keying method. Therefore, the receiving tuner for the data signal modulated according to the quadrature phase shift keying scheme can be downsized compared to the conventional one, and the configuration of the network interface module to which the tuner is applied can be simplified.

In the receiving tuner according to the fifth or sixth aspect, the signal conversion section oscillates at a frequency in accordance with the level of the tuning signal based on the information of the desired reception channel, and outputs the oscillation signal to the first frequency band signal. A mixing unit for mixing the oscillation signal output from the oscillation unit and converting the mixed signal into an intermediate frequency signal corresponding to a desired reception channel.

A voltage-controlled oscillation circuit may be applied to the above-described oscillation section. According to this configuration, the receiving tuner is configured so that the receiving frequency band is received only in the first and second frequency bands, so that the receiving range becomes narrower than in the past, and the signal of the internally oscillated signal is reduced. Appearance of phase noise in the received signal due to the influence can be suppressed. Therefore, the reception quality is improved. Further, since the configuration is simplified, power consumption and cost can be reduced.

[0051]

DESCRIPTION OF THE PREFERRED EMBODIMENTS ST according to an embodiment of the present invention
The configuration of the B40 except for the QPSK tuner 8 is the same as that shown in FIG.

FIG. 1 shows a QP according to an embodiment of the present invention.
FIG. 3 is a block diagram of the SK tuner 8. QPS of Fig. 1
The K tuner 8 is provided in place of the conventional QPSK tuner 8A shown in FIG.

The QPSK tuner 8 outputs a signal modulated according to the actually used QPSK method in the range of 70-13.
0 MHz and a signal having a band of 700 to 760 MHz, and the VHF HIGH BAND shown in FIG.
The receiving circuit for (170 to 470 MHz) is not used. Therefore, in the present embodiment, the receiving circuit for the unused receiving band is omitted as described later,
Furthermore, VH is applied by applying the double superheterodyne method.
A part of a receiving circuit for F BAND and a part for UHF BAND are configured to be shared.

In FIG. 1, the QPSK tuner 8 is
Input terminal 1, provided on the input side of the two-way distributor 22,
A VHF band BPF (abbreviation for band pass filter) 44 for passing an intermediate frequency signal of 70 MHz to 130 MHz (hereinafter referred to as a first intermediate frequency signal) in the F Low band;
A UHF band BPF 45 for passing a signal of 700 to 760 MHz in the UHF band, a first mixing circuit 46 for inputting an output signal of the UHF band BPF 45, converting the signal into a first intermediate frequency signal of 70 to 130 MHz, and outputting the first intermediate frequency signal; A circuit 47, a first local oscillation circuit 48 and a first intermediate frequency output circuit 49, a first intermediate frequency amplifier 50 for inputting, amplifying and outputting the first intermediate frequency signal, and a receiving channel for receiving the first intermediate frequency signal as desired A second mixing circuit 51 for converting the signal into an intermediate frequency signal (hereinafter, referred to as a second intermediate frequency signal) corresponding to the second local oscillation circuit 52 and a second local oscillation circuit 52 including an oscillation unit 521 and a PLL tuning unit 522; A second intermediate frequency amplifier 5 for inputting and amplifying the intermediate frequency signal and leading it to the output terminal 230 of the QPSK demodulator 11 shown in FIG.
3 inclusive.

In operation, a signal modulated in accordance with the QPSK system, which is a downstream signal output from the splitter 22 in FIG.
MHz BAND (LOW BAND) signal is VHF
Band BPF44, and U of 700MHz to 760MHz
The HF BAND signal is supplied to the UHF band BPF 45, and other CATV signals (digital QAM signal, analog NTSC signal, and signal modulated according to the QPSK method as an upstream signal) are removed. UHF band BPF45
The output UHF BAND signal is mixed by the first mixing circuit 46 with the frequency-multiplied wave of the first local oscillation circuit 48 and frequency-converted.

Specifically, the oscillation signal of the first local oscillation circuit 48 uses 103.75 MHz. The frequency of the signal output from the first local oscillation circuit 48 is multiplied by 8 by a multiplication circuit 47 to become 830 MHz, and the first mixing circuit 46
Is applied to The first local oscillation circuit 48 is a circuit having a fixed oscillation frequency, and an oscillation circuit using a crystal oscillator or the like is used. That is, the output of the UHF band BPF 45 output 700 to
The signal of 760 MHz is frequency-converted by the first mixing circuit 46 to become 70 to 130 MHz.
9 to a first intermediate frequency amplifier 50.

On the other hand, the LOW BAND signal is VHF
The signal is supplied to the first intermediate frequency amplifier 50 through the band BPF 44 in the same manner as the UHF BAND signal. This 70-130
The first intermediate frequency signal of MHz is frequency-converted to a second intermediate frequency signal by an oscillation signal of a second local oscillation circuit 52 in a second mixing circuit 51 and amplified by a second intermediate frequency amplifier 53, and then output to an output terminal. Derived from 230.

The second local oscillation circuit 52 is PLL-controlled and has a circuit configuration for selecting a signal modulated according to the QPSK system of 70 to 130 MHz in accordance with a desired reception channel. Specifically, the PLL tuning unit 52
Numeral 2 includes a VCO (Voltage Controlled Oscillator) to apply a tuning voltage corresponding to tuning data SD including desired reception channel information and band information to the oscillation unit 521,
Oscillates at a tuning frequency corresponding to a given tuning voltage.
Output from the first intermediate frequency signal (70 to 130 MHz)
z) is mixed with the oscillation signal output from the oscillation unit 521, converted into an intermediate frequency signal (second intermediate frequency signal) corresponding to the desired channel, and output.

FIG. 2 is a diagram showing a tank circuit of a VCO (voltage controlled oscillator) applied to the PLL tuning unit 522 of FIG. In FIG. 2, the tank circuit is a parallel tuning circuit of a resonance inductor L and resonance capacitors C1 and CT.
As described above, the reception frequency band of the downstream signal modulated according to the conventional QPSK is 54 to 860 MHz, whereas in the present embodiment, the reception is performed in the frequency band of 70 to 130 MHz for the VHF signal and 700 to 760 MHz for the UHF signal. Designed. This means that the oscillation frequency range of the VCO applied to the PLL tuning unit 522 becomes narrower than before. This means that the VCO shown in FIG.
Therefore, the figure of merit (Q) of the tank circuit applied to the VCO is improved, and the phase noise in the received signal due to the influence of the oscillation signal of the VCO is reduced.

As described above, in this embodiment, the QPS
The simplification of the configuration of the K tuner also simplifies the configuration of the NIM and STB to which it is applied.

Further, as described above, the QPS
A design is possible in which the reception range of the downstream signal modulated according to the K system is narrow, and the phase noise with respect to the reception signal is reduced. The reduction level of this phase noise is UHF
It is possible to improve by -10 dBc / Hz or more by BAND.

Further, by simplifying the configuration, the power consumption is reduced by 10% as compared with the conventional one and the cost is reduced by about 20% as compared with the conventional one.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[Brief description of the drawings]

FIG. 1 is a block diagram of a QPSK tuner according to an embodiment of the present invention.

FIG. 2 is a diagram showing a tank circuit of a VCO (Voltage Controlled Oscillator) applied to the PLL tuning unit of FIG. 1;

FIG. 3 is a block diagram of an STB applied to a conventional and an embodiment of the present invention.

FIG. 4 is a block diagram of the conventional QPSK tuner shown in FIG.

[Explanation of symbols]

 8,8A QPSK tuner 44 VHF band BPF 45 UHF band BPF 46 First mixing circuit 47 Multiplier circuit 48 First local oscillation circuit 51 Second mixing circuit 52 Second local oscillation circuit Note that the same reference numerals in each drawing denote the same or corresponding parts. Is shown.

Claims (6)

[Claims] 1. CATV (abbreviation for cable television)
A network interface module for transmitting / receiving a signal to / from a station via a cable line, comprising: an upstream signal transmitting unit for transmitting an upstream data signal to the CATV station to the cable line; A downlink signal introduction unit for introducing a downlink signal group including one or more types of signals from the CATV station from the cable line, and a reception for receiving the downlink signal group introduced by the downlink signal introduction unit. And a circuit unit, wherein the receiving circuit unit has at least a tuner for receiving a predetermined signal modulated according to a predetermined modulation scheme in the downlink signal group, and the tuner is configured to modulate the predetermined signal. And a filter unit for extracting a first frequency band signal by inputting a second frequency band. A filter conversion unit for extracting a signal while converting the signal into the first frequency band signal; and inputting the first frequency band signal output from each of the filter unit and the filter conversion unit to correspond to a desired reception channel. A signal conversion unit for converting the signal into an intermediate frequency signal and outputting the converted signal, wherein a band other than the first and second frequency bands in the reception frequency band of the predetermined signal is an unused band. . 2. The method according to claim 1, wherein the predetermined signal is a data signal, and the predetermined modulation scheme is a quadrature phase shift keying scheme that changes a phase of a carrier of the data signal according to a digital signal sequence indicating the data signal. The network interface module according to claim 1, wherein: 3. The signal conversion unit includes: an oscillating unit that oscillates at a frequency according to a level of a tuning signal based on information of the desired reception channel and outputs the signal; The network interface module according to claim 1, further comprising: a mixing unit configured to mix the output oscillation signal and convert the mixed signal into an intermediate frequency signal corresponding to the desired reception channel. 4. The network interface module according to claim 3, wherein a voltage-controlled oscillation circuit is applied to the oscillation unit. 5. CATV (abbreviation for cable television)
A receiving tuner for receiving a predetermined signal modulated according to a predetermined modulation scheme transmitted from a station, comprising: a filter unit that receives the modulated predetermined signal and extracts a first frequency band signal; A filter conversion unit that receives the predetermined signal and converts and extracts a second frequency band signal into the first frequency band signal; and the first frequency band output from each of the filter unit and the filter conversion unit. A signal conversion unit for receiving a signal, converting the signal into an intermediate frequency signal corresponding to a desired reception channel, and outputting the converted signal, wherein a band other than the first and second frequency bands in the reception frequency band of the predetermined signal is unused. A receiving tuner, which is a band. 6. The predetermined signal is a data signal, and the predetermined modulation method is a quadrature phase shift keying method that changes a phase of a carrier of the data signal according to a digital signal sequence indicating the data signal. The receiving tuner according to claim 5, characterized in that: