JPH04180376A - Wide aspect identification signal insertion circuit - Google Patents

Abstract

PURPOSE:To insert an identification signal not including a high frequency component by forming a mixing amplifier circuit with a wide aspect identification signal insertion circuit which synthesizes and amplifies a chrominance signal and a signal outputted from a filter. CONSTITUTION:A rectangular wave signal (a) is inputted to an LPF 3, and is changed to a band-limited signal (b), and is inputted to a switch 4. The switch 4 is activated either when the aspect ratio of an input video signal is 16:9 or 4:3, and at this time, the signal (b) is mixed and amplified with the chrominance signal (c) at the mixing amplifier circuit 5, and a signal (d) in which the identification signal (b) is inserted to the chrominance signal (c) is outputted. At a television receiver 6, the aspect ratio of the input video signal can be identified by the presence/absence of the identification signal (b). In such a way, it is possible to eliminate the high frequency component of the identification signal formed with a rectangular wave by providing a low-pass filter and passing the identification signal through it.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a wide aspect identification signal insertion circuit.

Conventional technology In recent years, the screens of television receivers (hereinafter referred to as televisions) have become wider and wide aspect (16:9) broadcasting has been put into practical use. Measures to increase the width are required. That is, when inputting a video signal reproduced by a video reproduction device to a television, the video reproduction device must insert into the video signal a signal that allows the television to identify the aspect ratio of the signal.

A conventional wide aspect identification signal insertion circuit will be described below.

FIG. 3 is a block diagram showing the configuration of a conventional wide aspect identification signal insertion circuit. FIG. 4 is a circuit diagram showing the configuration of the wide aspect identification signal generation circuit 8 in FIG. . Further, FIG. 5 is a waveform diagram showing the signal waveform at the connection point em in FIGS. 3 and 4. In the above configuration, the mutual relationship and operation of the components will be explained.

In FIG. 3, a horizontal synchronizing signal f is separated from the input luminance signal M by a horizontal synchronizing signal separating circuit 7, and the horizontal synchronizing signal f is inputted to a wide aspect identification signal generating circuit 8.

In FIG. 4, the signal f input to the wide aspect identification signal generation circuit 8 is input to the sufficient frequency circuit 9 to become a signal g having a frequency of 10, and is input to the ND circuit 10 and the NARD circuit 12. . Also, the signal g is AND
The signal is input to the circuit 10 and is also input to the WAND circuit 12 as a signal i whose polarity is inverted by the inverter 11 .

The fifth ND circuit 10 generates the signal 1 from the signals g and f, and the second ND circuit 12 generates the signal j from the signals i and f, and the signals ri and j are mixed, and the polarity is reversed every horizontal scanning period. It is output as an identification signal.

The identification signal is then input to the switch 13; this switch 13 inputs the input video signal with an aspect ratio of 16:
By the signal S indicating whether it is 9 or 4:3,
It is turned ON when the aspect ratio is one of the above, and turned OFF when the aspect ratio is other than the above.

Therefore, if the aspect ratio is 16:9″!i or 4
:3, the switch 13 is turned on, and at this time the signal k is mixed and amplified with the color signal l in the mixing/amplifying circuit 14, and a signal m with the identification signal k inserted into the color signal 1 is output. Ru.

The television receiver 15 identifies the aspect ratio of the input video signal based on the presence or absence of the identification signal.

Problems to be Solved by the Invention However, in such a conventional identification signal insertion circuit,
Since the generated identification signal is a rectangular wave, it contains high-order harmonic components. Therefore, when the identification signal k is removed from the signal m on the television receiver side, it cannot be removed by a filter with gentle characteristics. , a filter with steep characteristics is required.

For this reason, there is a delay in the color signal, and the luminance signal must also be delayed accordingly.
There was a problem in that the cost increased accordingly.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a wide aspect identification signal insertion circuit that does not require a delay line for a luminance signal.

Means for Solving the Problems In order to achieve the above object, the present invention provides a circuit that separates and outputs a horizontal synchronization signal from an input luminance signal, and a circuit that separates and outputs a horizontal synchronization signal from an input luminance signal, and a circuit that separates and outputs a horizontal synchronization signal as a wide aspect identification signal every horizontal synchronization period while synchronizing with the luminance signal. a circuit that forms a rectangular wave signal whose polarity is inverted, a low-pass filter that inputs the identification signal and limits the band, and mixes and amplifies the output of the filter when the wide aspect ratio is a predetermined value. A switch connected to the circuit is provided,
The mixing amplification circuit is a wide aspect identification signal insertion circuit that combines and amplifies the color signal and the signal output from the filter.

In the above structure, the horizontal synchronization signal separation circuit separates the horizontal synchronization signal, the wide aspect identification signal generation circuit generates a horizontally synchronized identification signal, and the low-pass filter extracts the high frequency component of the identification signal. remove. A mixing amplifier circuit combines the identification signal from which the high frequency component has been removed with the color signal.

Embodiment Hereinafter, a wide aspect identification signal insertion circuit according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a wide aspect identification signal insertion circuit according to an embodiment of the present invention.

In the figure, 3 is a low pass filter (hereinafter referred to as LPF) and 4 is a switch.

Further, FIG. 2 is a waveform diagram showing signal waveforms at connection points a to d in FIG. 1.

In FIG. 1, a horizontal synchronizing signal is separated from an input luminance signal V by a horizontal synchronizing signal separating circuit 1, and the separated horizontal synchronizing signal is input to a wide aspect identification signal generating circuit 2. The identification signal generation circuit 2 generates a rectangular wave signal a whose polarity is inverted every horizontal scanning period from the input horizontal synchronizing signal.
occurs. The above operation is exactly the same as that of the conventional wide aspect identification signal insertion circuit described above, so the explanation will be omitted.

Next, the rectangular wave signal a is input to the LPF 3, and is input to the switch 4 as a band-limited signal. As in the case of the conventional method, the switch 4 is turned on when the aspect ratio of the input video signal is either 16:9 or 4:3, and at this time the signal is converted to the color signal C by the mixing/amplifying circuit 6. The signal d is mixed and amplified with the color signal C and the identification signal d is output.

The television receiver 6 identifies the aspect ratio of the input video signal based on the presence or absence of the identification signal.

As described above, according to the wide aspect identification signal insertion circuit of the embodiment of the present invention, by providing a low-pass filter and passing the identification signal, the high-frequency component of the identification signal formed by a rectangular wave can be removed. Can be removed.

Effects of the Invention As is clear from the embodiments described above, the present invention includes a circuit that separates and outputs a horizontal synchronizing signal from an input luminance signal, and a circuit that separates and outputs a horizontal synchronizing signal from an input luminance signal, and a circuit that separates and outputs a horizontal synchronizing signal as a wide aspect identification signal, and a circuit that separates and outputs a horizontal synchronizing signal as a wide aspect identification signal. a circuit that divides the inverted rectangular wave signal, a low-pass filter that inputs the identification signal and limits the band, and a mixing amplifier circuit that mixes the output of the filter when the wide aspect ratio is a predetermined value. and a wide aspect identification signal insertion circuit in which the mixing amplifier circuit synthesizes and amplifies the color signal and the signal output from the filter. Signals can be inserted.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a wide aspect identification signal insertion circuit according to an embodiment of the present invention, FIG. 2 is a waveform diagram showing waveforms in the wide aspect identification signal insertion circuit according to an embodiment of the invention, and FIG. Figure 4 is a block diagram showing the configuration of a conventional wide aspect identification signal insertion circuit, Figure 4 is a circuit diagram showing the configuration of an identification signal generation circuit, and Figure 6 is a waveform showing waveforms in the identification signal generation circuit and the conventional insertion circuit. It is a diagram. 1...Horizontal synchronization signal separation circuit, 2...
Wide aspect identification signal generation circuit, 3...Low pass filter, 4...Switch, 6...Mixing/amplification circuit, C...Color signal input , d...
...output, ma...brightness signal input. Name of agent: Patent attorney Akira Okaji and two other people.
Sururu…31st ward Mi＼r Cfu wrinkles

Claims (1)

[Scope of Claims] A circuit that separates and outputs a horizontal synchronization signal from an input luminance signal, and a circuit that forms a rectangular wave signal whose polarity is inverted every horizontal synchronization period while synchronizing with the luminance signal as a wide aspect identification signal. and a low-pass filter that inputs the identification signal to limit the band; and a switch that connects the output of the filter to a mixing amplifier circuit when the wide aspect ratio is a predetermined value; A wide aspect identification signal insertion circuit, the circuit combining and amplifying a color signal and a signal output from the filter.