JPH035709B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a television synchronization receiver that can be used in television receivers and VTR video tuners.

Conventional configurations and their problems In recent years, so-called electronic tuners that use variable capacitance diodes as tuning elements have been widely used in television receivers and VTR video tuners. Electronic tuners have advantages such as being non-contact, so there is no problem of contact failure, and being electronically controllable, making them convenient for multiple functions such as remote control. However, due to variations in the characteristics of variable capacitance diodes and the need for inductance for tuning, it is difficult to make adjustments and automate their manufacturing.

Therefore, in order to configure a receiver that is easy to integrate without using a tuning circuit using a variable capacitance diode and an inductor, it is possible to use a synchronous reception method. Although there are various synchronous reception methods, a synchronous carrier regeneration method is suitable for phase-synchronizing a synchronous carrier wave with a weak television signal. This method is called Costas loop.
known as the method.

FIG. 1 is a main part block diagram showing the configuration of a conventional synchronous carrier regeneration type synchronous receiver using a Costas loop. 1 is a first synchronous detector that synchronously detects the in-phase component of a modulated carrier input; 2 is a second synchronous detector that synchronously detects a quadrature component; 3 and 4 are each of these two synchronous detectors 1 and 2; 5 is a phase detector that detects the phase of the synchronous carrier with respect to the modulated carrier by voltage multiplying the outputs of these two low-pass filters 3 and 4; 6 is a phase detector that performs low-pass filtering of the output; 7 is a voltage controlled oscillator controlled by the output of this low pass filter 6; 8 is this voltage controlled oscillator 7;
This is a 90° phase shifter that shifts the phase of the output by 90°.

In this Costas loop type synchronous receiver, the first
and the in-phase and quadrature component signals obtained from the second synchronous detectors 1 and 2 are applied to the phase detector 5, and from this phase detector 5, the receiver input, that is, the modulated carrier wave, and the output of the voltage controlled oscillator 7, that is, the synchronous carrier By obtaining a voltage proportional to the phase error between the two and feeding back this voltage to the voltage controlled oscillator 7, the phase error is controlled to be zero.

If the conventional example shown in Fig. 1 is applied directly to a television receiver, the baseband video signal of the desired channel to be received can be obtained by synchronous detection, and the audio intermediate frequency signal can also be obtained. Generates a carrier color signal and a carrier audio signal for the channel. The carrier color signal and carrier audio signal of the lower adjacent channel are mixed into the synchronously detected baseband video signal as an interference signal.

As a countermeasure, it is possible to remove the lower adjacent channel by installing a tuning circuit using a variable capacitance diode and an inductor in the high frequency input section.
This deviates from the original purpose of constructing a receiver without using these elements.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a television synchronization receiver capable of eliminating interference of a carrier color signal and a carrier audio signal of a lower adjacent channel to a baseband video signal of a channel desired to be received.

Structure of the Invention The television synchronized receiver of the present invention includes a voltage controlled oscillator and a phase adjustment of the output of the voltage controlled oscillator.
a 90° phase shifter that shifts the phase by 90°; a first synchronous detector that synchronously detects the in-phase component of the video carrier signal using the synchronous carrier output from the voltage controlled oscillator;
A second synchronous detector that synchronously detects the orthogonal component of the video carrier signal using the synchronous carrier output from the 90° phase shifter, and a second synchronous detector that synchronously detects the orthogonal component of the video carrier signal using the synchronous carrier wave output from the 90° phase shifter; a first low pass filter that low pass filters the signal in a frequency range;
A second low-pass filter that low-pass filters the output of the second synchronous detector in the frequency range of the video signal baseband and the audio intermediate frequency signal, and is connected to the first and second low-pass filters. third and fourth low pass filters for obtaining low pass filtered signals narrow enough to impart small frequency fluctuations to the converted video carrier of the lower adjacent channel; a phase detector for detecting a phase difference between the video carrier signal and the output of the voltage controlled oscillator from the output of the bandpass filter; a feedback means for feeding back the output of the phase detector to the voltage controlled oscillator; A signal amplifier amplifies the output of the low-pass filter, and converts the baseband video signal in the output of this signal amplifier into an analog
an A/D converter that performs digital conversion; a clock generator that separates a television synchronization signal or a color burst signal from the output of the signal amplifier and generates a clock signal by controlling the signal; A time-direction low-pass filter operates with the signal output from the A/D converter as input and the signal output from the clock generator as a clock, and the output of this time-direction low-pass filter is converted from digital to analog. A television synchronized reception device comprising a D/A converter and using the output of the D/A converter as a video signal, wherein the temporal low-pass filter converts the output of the A/D converter into a video signal. to (1-
K) and a signal obtained by multiplying the output of the frame memory below by a coefficient K, a computing unit that adds the signal obtained by multiplying the output of the frame memory below by a coefficient K, a frame memory that stores the output of this computing unit for each frame, and the output of the A/D converter mentioned above. a motion detector that detects the movement of an image between frames from the difference between the output of the frame memory and the output of the frame memory; a coefficient generator that determines the coefficient K based on the output of the motion detector; and an output of the coefficient generator. an address generator for determining the address of the frame memory according to the clock signal generated from the clock generator; The frame memory is configured to include a memory controller for writing or erasing information into the frame memory, and an input means for inputting the output of the memory controller to the frame memory, and the first low-pass filter inputs the output of the memory controller to the lower adjacent channel. In addition to removing the main part of the energy of the video signal, the temporal low-pass filter lowers the interference of the carrier color signal and the audio intermediate frequency signal of the lower adjacent channel to the baseband video signal. be.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows a block diagram of essential parts of a television synchronization receiver according to an embodiment of the present invention. In FIG. 2, 9 is a high frequency input section, 10 is a first synchronous detector, 11 is a second synchronous detector, 1
2 and 13 are first and second low pass filters, 1
4 and 15 are signal amplifiers, 16 and 17 are third and fourth low-pass filters, 18 is a phase detector,
19 is a low-pass filter of the Costas loop, 20 is a voltage controlled oscillator, and 21 is a 90° phase shifter, and these constitute the Costas loop. 22 is an audio intermediate frequency amplifier, 23 is a frequency discriminator, 24 is a voltage subtractor, and 25 is a low-pass filter, which constitute a frequency pull-in circuit, and the output thereof is sent to a voltage adder 26.
is added to the output of the low-pass filter 19 of the Costas loop. 27 is a voltage storage device, 28 is a voltage selector, and 29 is a control signal input device, which constitute a channel selection voltage generation circuit. The output voltage of the voltage selector 28 is also summed in a voltage adder 26 with the output of the low-pass filter 19 of the Costas loop. 30 is an A/D converter that converts the output of the signal amplifier 14 into analog/digital; 31 also separates a television synchronization signal or a color burst signal from the output of the signal amplifier 14; This is a clock generator that controls and generates a clock signal. 32 is the above A/D converter 30
An arithmetic unit that adds a signal obtained by multiplying the output of 1-K by K and a signal obtained by multiplying the output of the frame memory 33 described below by K, 33 is a frame memory that stores the output of this arithmetic unit for each frame, and 34 is this frame A chroma inverter 35 inverts the phase of the color signal of the color television signal stored in the memory for each frame, and detects the movement of the image between frames from the difference between the output of this chroma inverter and the output of the A/D converter 30. motion detector to detect, 3
6 is a coefficient generator that determines the coefficient K based on the output of the motion detector; 37 is an address generator that determines the address of the frame memory based on the clock signal from the clock generator 31;
8 is a memory controller that writes and erases the frame memory according to the address determined by this address generator, and these constitute a motion-adaptive temporal low-pass filter. 39 is a video signal filter, 40 is a D/A converter for digital-to-analog conversion of the output of the video signal filter, 41 is a video output circuit, and 42 is an audio output circuit.

The operation of the television synchronized receiver of this embodiment configured as described above will be explained below. The video carrier signal of the desired channel input to the high frequency input section 9 is V _{v (t), and the audio carrier signal is V v} (t).
Let V _s (t). Since V _v (t) is subjected to residual sideband modulation, it can be expressed as follows.

V _v (t)=Re {[I(t)+jQ(t)]expj[ωvt+v]} =I(t)cos(ωvt+v)−Q(t)sin(ωvt+v)
...(1) Here, Re is the real part of the expression in { }.
I(t) is a signal having an in-phase component with respect to the carrier wave, and includes a video signal. Q(t) is a signal of a component orthogonal to the carrier wave, ωv is the angular frequency of the video carrier wave, and v is the phase of the video carrier wave.

Furthermore, the narrowband Gaussian noise n(t) is set as n(t)=n _c (t)cos (ωvt+v) −n _s sin(ωvt+v) ……(2), and the above V _v (t) and this n(t) is applied to one terminal of each of the first and second synchronous detectors 10 and 11.

Now let the output of the voltage controlled oscillator 20 be V ₀ (t)=A ₀ cos (ω ₀ t+ ₀ )...(3) and apply it to the other terminal of the first synchronous detector 10 consisting of a voltage multiplier. and its output V _pv (t)
is, V _pv (t)=A ₀ [V _v (t)+n(t)] cos (ω ₀ t+ ₀ ) = A ₀ /2 [I(t)+n _c (t)] {cos [ω _v + ω ₀ ) t + _v + ₀ ] +cos [(ω _v −ω ₀ ) t+ _v − ₀ ]} −A ₀ /2 [Q(t)+n _s (t)] {sin [(ω _v + ω ₀ ) t+ _v + ₀ ] + sin [(ω _v − ω ₀ ) t+ _v − ₀ ]}...(4) When the voltage controlled oscillator output is synchronized with the video carrier wave, ω ₀ = ω _v , so V _pv (t) = A ₀ /2 [I(t) + n _c (t)] {cos [2ω _v t + _v + ₀ ) + cos ( _v − ₀ )} −A ₀ /2 [Q(t) + n _s (t)] { sin (2ω _v t + _v + ₀ ) + sin ( _v −ψ ₀ )} ...(5) When the 2ω _v signal is removed by the low-pass filter 12, V _pv (t)=A ₀ /2 [I(t )＋n _c (t)〕cos −A ₀ /2〔Q(t)＋n _s (t)〕sin ……(6) Here, is _v −ψ ₀ , and the position between the video carrier wave and the voltage-controlled oscillator output is There is a phase difference. If = 0, V _pv (t) = A ₀ /2 [I(t) + n _c (t)] ...(7). In other words, the signal and noise of the in-phase component with respect to the video carrier wave are obtained as the detection output. However, orthogonal components are not detected. This detection output is passed through a low-pass filter 12 to a signal amplifier 14 as a video detection output.
The signal is amplified by the D/A converter 40 and output to a temporal low-pass filter, which will be described later. The filtering characteristics of the low-pass filter 12 are shown in FIG. The video signal is filtered at baseband as shown in this figure. When a television signal is received using the conventional superheterodyne reception method, the overall baseband frequency characteristic can be considered to be flat due to the Nyquist filtering characteristics of the intermediate frequency amplifier. In this method, it must be assumed that the system is as shown in Figure 4a. That is, the voltage gain in the low frequency range is twice the gain in the high frequency range. Therefore, in the embodiment shown in FIG. 2, the frequency characteristics of the video signal filter 39 are corrected as shown in FIG. 4b.

Since the audio carrier signal V _s (t) of television broadcasting is frequency modulated, it can be expressed as V _s (t)=A _s cos [{ω _s +s(t)}t+ _s ] (8).

Here, A _s is the amplitude of the audio carrier signal, ω _s is the angular frequency of the audio carrier signal, S(t) is the audio signal, and _s is the phase of the audio carrier signal.

When this V _s (t) and V ₀ (t) of Equation 3 are added to the synchronous detector 10, the output is V _ps (t) = A _s coS [{ω _s + S(t)}t + _s ] A ₀ cos (ω ₀ t+ ₀ ) = A _s A ₀ /2cos [(ω _s + ω ₀ )t+S(t)t+ _s + ₀
] +A _s A ₀ /2cos [(ω _s −ω ₀ )t+S(t)t+ _s − ₀
] ...(9) When the frequency component of ω _s + ω ₀ is removed by the low-pass filter 12, V _ps (t)=A _s A ₀ /2cos [(ω _s −ω ₀ )t+S(t)t+ _s − ₀ ] ...(10) If ω _IF = ω _s −ω ₀ and ω ₀ = ω _v , then V _ps (t)=A _s A ₀ /2cos [{ω _IF +S(t)}t+ _s − ₀ ] ...(11) V _ps (t) in equation (10) is nothing but the audio carrier signal shown in equation (8) converted into an audio intermediate frequency signal with an angular frequency of ω _IF .

The filtering characteristics of the low-pass filter 12 are designed to cover the frequency ω _IF of the audio intermediate frequency signal, as shown in FIG. The audio intermediate frequency signal passes through this low-pass filter 12 and is amplified by a signal amplifier 14 and an audio intermediate frequency amplifier 22. The output is demodulated by a frequency discriminator 23 to obtain an audio signal S(t).
S(t) is supplied to the audio output circuit 42.

The carrier television signal is made up of signals having a frequency relationship as shown in FIG. 5a. The desired channel to receive is shown on the right, and the lower adjacent channel is shown on the left. The television signal of the desired channel is synchronously detected by the synchronous detector 10, and a baseband video signal, a carrier color signal, and a carrier color signal as shown in FIG.
The television signal of the lower adjacent channel is also converted by the synchronous detector 10 into an adjacent carrier video signal, an adjacent carrier color signal, and an adjacent carrier audio signal as shown in FIG. 5c.

The shaded part in Fig. 5c is the synchronous detector 1.
The zero output is removed when it passes through the low pass filter 12. This portion contains most of the adjacent carrier video signal. However, signals other than the shaded portion in FIG. 5c are mixed into the baseband video signal in FIG. 5b.

Next, the operation for removing the adjacent carrier video signal and adjacent carrier audio signal mixed into the baseband video signal will be described.

Since the output V ₀ (t) of the 90° phase shifter has a phase difference of 90° with the output of the voltage controlled oscillator 20, V ₀ (t)=A ₀ sin (ω ₀ t+ ₀ )...(12) This is added to the second synchronous detector 11 consisting of a voltage multiplier along with V _v (t) in equation (1), and its output V _pp (t)
When passed through the low-pass filter 13, V _pQ (t)=−A ₀ /2 [I(t)+n _c (t)] cos −A ₀ in the same way as when formula (6) was obtained. /2 [Q(t)+n _s (t)] sin ... (13) However, it is assumed that ω ₀ =ω _v . This V _pQ (t) is amplified by a signal amplifier 15 and applied to a phase detector 18 . In the phase detector 18 consisting of a voltage multiplier, V _pv
(t) and V _pQ (t) are voltage multiplied, resulting in the control voltage
V _c (t) occurs.

V _c (t) = V _pv (t)・V _pQ (t) = −A ² ₀ /8 {[I(t) + n _c (t)] ² − [Q(t) + n _s (t)] ² }sinθ −A ² ₀ /4 [I(t)+n _c (t)] [Q(t)+n _s (t)] cos θ ... (14) Here, θ=2. However, the amplification degrees of the first and second signal amplifiers are assumed to be 1 here.

The video carrier signal V _v (t) is transmitted through vestigial sideband transmission, but its transmission characteristics are different from normal vestigial sideband transmission, as it consists of a double sideband transmission part and a single sideband transmission part. It's on. That is, Figure 6a
The residual sideband characteristic of the video carrier signal V _v (t) shown in FIG. 6 is a superposition of the double sideband characteristic shown in FIG. 6b and the single sideband characteristic shown in FIG. 6c.

A signal by double sideband transmission consists only of in-phase components with respect to the phase of the carrier wave, and a signal by single sideband transmission consists of in-phase components and orthogonal components. Now, I _L (t) is the in-phase component of the signal V _v (t) due to double sideband transmission, I _U (t) is the in-phase component of the signal V _v (t) due to single sideband transmission, and Q _U (t)
Let be the orthogonal component of the signal V _v (t) due to single sideband transmission,
Setting I(t)=I _L (t)+I _U (t) and Q(t)=Q _U (t), formula (14)
is, V _c (t) = −A ² ₀ /8 {[I _L (t) + I _u (t) + n _c (t)] ² − [Q _u (t) + n _s (t)] ² } sinθ − A ² ₀ /4 [I _L (t) + I _u (t) + n _c (t)] [Q _u (t) + n _s (t)] cos θ ... (15).

If the low-pass filter characteristics of the low-pass filters 16 and 17 are set to FIG. 7 or narrower than that shown in FIG.
If the passband width is set to be narrower than 0.75MHz, I _u (t) and Q _u (t) in equation (15) are removed, and V _c
(t) is expressed by the following formula.

V _c (t) = −A ² ₀ /8 {[I _L (t)+n′ _c (t)] ² − [n′ _s (t)] ² }
sinθ −A ² ₀ /4 [I _L (t)+n′ _c (t)] [n′ _s (t)] cosθ……
(16) where n' _c (t) and n' _s (t) are the in-phase and quadrature components of narrowband Gaussian noise n(t) after passing through the low-pass filters 16 and 17. In other words, the video signal V _v (t)
The extent to which the local oscillator is frequency modulated by the influence of can be significantly reduced.

If I _L (t)≧n′ _c (t), I _L (t)≧n′ _s (t), then V _c (t)=−A ² ₀ /8 [I _L (t)] ² sinθ −A ² ₀ /4 [I _L (t)] [n′ _s (t)] cosθ ... (17) [I _L (t)] Since ² ≠ 0, the loop bandwidth is the second If it is narrow enough to remove the term component, then
The voltage controlled oscillator 20 is controlled so that θ=0. In other words, the phase error between the video carrier signal V _v (t) and the output V ₀ (t) of the voltage controlled oscillator 20 is =0.
The state will be as follows.

Even if the loop bandwidth is set sufficiently narrow to 0, the average value of will be 0, and a certain amount of the noise component represented by the second term of equation (17) will remain. This noise component is generated by the voltage controlled oscillator 20
gives fluctuations to the output phase and output frequency.

However, when comparing the second term of equation (17) with the second term of equation (15), the difference in amplitude is significantly large.

This is because Q _U (t)≧n _S (t), _s (t) ² >′ _s (t) ² , and I _U (t) is not included in equation (17).

However, _s (t) ² and ′ _s (t) ² are n _s (t) and n′ respectively
_s (t)
is the variance of

That is, by inserting the low-pass filters 16 and 17 as shown in FIG. 2, the influence of the noise component, that is, the second term in equation (15) or the second term in equation (14), can be significantly reduced. can.

Furthermore, if the bands of the low-pass filters 16 and 17 are made narrower, the dispersion ' _s (t) ² of n' _s (t) becomes smaller in proportion to the band. The fluctuations in the output phase and output frequency of the voltage controlled oscillator 20 are reduced accordingly. However, this frequency fluctuation does not completely disappear, but remains, albeit slightly. This residual frequency fluctuation causes frequency fluctuations in the synchronous detector 10 to the audio signal carrier of the channel desired to be received, the video carrier of the lower adjacent channel, and the audio carrier. This is because the synchronous detector 10 consists of a voltage multiplier, and this voltage multiplier converts the frequency of the signal from the high frequency input section 9 using the output from the voltage controlled oscillator 20.

Television audio signals are frequency modulated and the maximum frequency deviation is ±25KHz. If the fluctuation given to the audio signal carrier of the channel desired to receive is about 20 to 30 Hz, the signal-to-noise ratio of the demodulated audio signal is about 60 dB, and this level of signal-to-noise ratio is permissible. On the other hand, if frequency fluctuations of several Hz to 20 to 30 Hz are applied to the video carrier wave of the lower adjacent channel, the frequency spectrum of the carrier color signal of the lower adjacent channel will also fluctuate to the same extent, resulting in the baseband video signal of the desired channel being received. Also, unlike the spectrum of the carrier color signal, the spectrum does not have energy concentrated at each frame frequency (30Hz). The audio carrier wave of the lower adjacent channel will also fluctuate to the same extent, but since the audio carrier wave is frequency modulated, the spectrum of the carrier audio signal originally has a frequency width of about ±100 KHz.

Arithmetic unit 32, frame memory 33, chroma inverter 34, motion detector 35, coefficient generator 3
6, an address generator 37, and a memory controller 38. The temporal low-pass filter is known as a noise reducer. This temporal low-pass filter is a recursive filter having a delay element for one frame of the video signal, and is a circuit that temporally averages the video signal for each frame period. As shown in FIG. 8, its frequency characteristic is a comb shape that repeats at the frame frequency. Moreover, the depth of the valley of this frequency characteristic changes according to the coefficient K. This coefficient K is then a function of the interframe difference signal examined by the motion detector 35.

Part of the carrier color signal, carrier audio signal, and carrier video signal of the lower adjacent channel frequency-converted by the synchronous detector 10 has a fluctuating spectrum, so it is processed by the motion-adaptive temporal low-pass filter. Most of it is removed. In this case, since it is a motion-adaptive type, in the moving image part, K→0 is set to lower the blurring, and when the image is close to a still image, K is increased to increase the degree of interference signal removal. In this way, interference from the lower adjacent channel mixed into the baseband video signal of the channel desired to be received can be removed.

Finally, the operation of the television receiver of this embodiment to select a desired channel for reception and enter the reception state will be explained. The voltage storage device 27 corresponds to the desired reception channel input from the control input device 29.
The voltage selector 28 selects the channel selection voltage stored in the voltage selector 28 and applies it to the voltage adder 26. The voltage controlled oscillator 20 is controlled by this channel selection voltage to generate a synchronous carrier wave V ₀ (t). The audio carrier wave V _s (t) and this synchronous carrier wave V ₀ (t) are applied to a synchronous detector 10, resulting in the generation of an audio intermediate frequency signal V _ps (t). This audio intermediate frequency signal is extracted by the early frequency pull-in circuit.
Video carrier wave V _v (t) on which the frequency of V _ps (t) is broadcasted
The frequency of the synchronous carrier wave _V 0 (t) is controlled so as to be equal to the difference between the carrier frequency ω v (t) of the audio carrier wave V _s (t) and the carrier frequency ω _s (t) of the audio carrier wave V _s (t), that is, ω _IF . When this frequency falls into the frequency pull range of the Costas loop, the Costas loop rapidly enters a state of phase locking. When the Costas loop is phase synchronized, the synchronous detector 10 outputs the video signal V _pv (t) and the audio intermediate frequency signal.
V _ps (t) is obtained. These signals are filtered by low pass filter 1
2, etc., the video signal is output to the video output circuit 41, and the audio intermediate frequency signal is demodulated by the frequency discriminator 23, and the demodulated audio signal is output to the audio output circuit 42.

Effects of the Invention As is clear from the above explanation, in the present invention, the frequency range of the baseband video signal and the frequency of the audio intermediate frequency signal are the low-pass filtering range of the baseband video signal synchronously detected by the Costas loop. Most of the energy of the carrier video signal of the lower adjacent channel is removed by low-pass filtering with a low-pass filter, and this baseband video signal is further subjected to frame frequency interval comb filtering with a temporal low-pass filter. Therefore, most of the interference of the carrier color signal and carrier audio signal of the lower adjacent channel to the baseband video signal to be received can be removed. That is, the number of carrier waves in the lower adjacent channel is
By applying a frequency fluctuation of about Hz or 20 to 30 Hz, the same degree of fluctuation is also applied to the frequency spectrum of the carrier color signal of the lower adjacent channel, and this fluctuation causes the baseband video signal and carrier color signal of the desired channel to be received. By preventing a spectrum in which energy is concentrated at each frame frequency (30 Hz), the motion-adaptive temporal low-pass filter can completely remove the lower adjacent channel signal in which this spectrum fluctuates. Furthermore, since the temporal low-pass filter is of a motion-adaptive type, the above-mentioned interference removal effect is particularly great when the video signal desired to be received is close to a still image.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the main part of a conventional television synchronous receiver, Fig. 2 is a block diagram of the main part of an embodiment of the present invention, and Fig. 3 shows the frequency of a low-pass filter that filters the output of a synchronous detector. Characteristic diagrams. Figure 4a is a baseband frequency characteristic diagram of the video signal, Figure 4b is a frequency characteristic diagram of the video signal filter, and Figure 5a is the frequency of the desired reception channel and lower adjacent channel of the television signal. A diagram showing the relationship, FIG. 5b is a diagram showing the frequency conversion relationship of the desired reception channel,
Figure c is a diagram showing the frequency conversion relationship of the lower adjacent channel, Figure 6a is a characteristic diagram of vestigial sideband transmission of a television signal, and Figure 6b is a diagram showing both side waves during vestigial sideband transmission of a television signal. Figure 6c is a characteristic diagram showing single sideband transmission during vestigial sideband transmission of a television signal; Figure 7 is a frequency characteristic diagram of the third and fourth low-pass filters. 8 shows the frequency characteristics of the motion-adaptive temporal low-pass filter. 10...First synchronous detector, 11...Second synchronous detector, 12...First low-pass filter, 13...
second low-pass filter, 16... third low-pass filter,
17... Fourth low-pass filter, 18... Phase detector, 20... Voltage controlled oscillator, 21... 90° phase shifter, 32... Arithmetic unit, 33... Frame memory, 35... Movement Detector, 36... Coefficient generator.

Claims (1)

[Claims] 1. A voltage controlled oscillator, a 90° phase shifter that shifts the phase of the output of the voltage controlled oscillator by 90°, and a first device that synchronously detects the in-phase component of the video carrier signal using the synchronous carrier wave output from the voltage controlled oscillator. a second synchronous detector that synchronously detects the orthogonal component of the video carrier signal using the synchronous carrier output from the 90° phase shifter; A first low-pass filter performs low-pass filtering in the frequency range of the baseband and audio intermediate frequency signals, and low-pass filters the output of the second synchronous detector in the frequency range of the video signal baseband and audio intermediate frequency signals. a second low-pass filter connected to said first and second low-pass filters, and a low-pass filtered signal of a band narrow enough to impart a small frequency fluctuation to the converted video carrier of the lower adjacent channel; third and fourth low-pass filters for obtaining the desired voltage, and phase detection for detecting the phase difference between the video carrier signal and the output of the voltage-controlled oscillator from the outputs of the third and fourth low-pass filters. a feedback means for feeding back the output of the phase detector to the voltage controlled oscillator, a signal amplifier for amplifying the output of the first low-pass filter, and a baseband video signal in the output of the signal amplifier. an A/D converter that converts from analog to digital;
a clock generator that separates a television synchronization signal or a color burst signal from the output of the signal amplifier and generates a clock signal by controlling the signal; and a signal output from the A/D converter. It is composed of a time-direction low-pass filter that receives as input and operates as a clock the signal output from the clock generator, and a D/A converter that converts the output of the time-direction low-pass filter from digital to analog. In the television synchronization receiving device which uses the output of the D/A converter as a video signal, the temporal low-pass filter receives a signal obtained by multiplying the output of the A/D converter by (1-K). and a signal obtained by multiplying the output of the frame memory below by a coefficient K, a frame memory that stores the output of this calculator for each frame, and the output of the A/D converter and the output of the frame memory. a motion detector that detects the movement of the image between frames from the difference between the frames;
a coefficient generator for determining the coefficient K based on the output of the motion detector; means for inputting the output of the coefficient generator to the arithmetic unit; An address generator that determines the address of the frame memory, a memory controller that writes or erases the frame memory according to the address determined by the address generator, and an input means that inputs the output of the memory controller to the frame memory. What is claimed is: 1. A television synchronous receiving device comprising: