JPH039424Y2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to a television receiver, and particularly to a color television receiver capable of receiving teletext signals.

(b) Prior Art When text multiplex broadcasting is implemented, a demand arises for text information to be recorded on a video tape recorder (hereinafter referred to as "VTR").

However, in VTRs that use a generally popular 1/2-inch tape, it is difficult to record character signal data inserted into the vertical blanking period of a composite video signal onto the tape. This is because this type of character signal data is a signal with a very high frequency and is in digital format.

(c) Purpose of the invention The main purpose of the invention is to provide a color television receiver at a low cost, which is capable of providing a character signal obtained by reproducing character signal data to a VTR in a form that can be recorded.

Another object of the present invention is to provide a VTR with the ability to provide character signals with unimpaired color fidelity.

(d) Structure of the invention The present invention provides a character multiplexing switching circuit 5 for outputting R, G, and B signals in which character signals are multiplexed in a color television receiver for receiving a character multiplexing signal.
and the above R, from this character multiplex switching circuit 5.
an output amplifying circuit 7 for amplifying the G, B signals; a color cathode ray tube 8 to which the output of the output amplifying circuit 7 is input; and the R, G,
A matrix circuit 10 that receives the B signal and outputs I, Q, and Y signals, and an I signal filter 12 that receives the I signal and has a wide passband.
, a Q signal filter 14 to which the Q signal is input and whose pass band is set wide; the I signal filter 12; I and Q modulation circuits 13 and 15 that respectively modulate the signals from the Q signal filter 14; Q
It is characterized by comprising an amplifier 24 into which the outputs of the modulation circuits 13 and 15 and the Y signal are input, and outputs a signal to an output terminal 25.

(E) Embodiment In FIG. 1, 1 is a first video amplifier, 2 is a video output terminal, 3 is a bandpass amplifier, 4 is a video chroma processing block, and 5 is a character multiplex signal switching circuit. The video output of the video amplifier 1 is applied to the video chroma processing block 4 through the character multiplexing switching circuit 5, and its color signal is applied to the video chroma processing block 4 through the bandpass amplifier 3. As a result, the video chroma processing block 4 provides R, G, and B signals. These R, G, and B signals are formed from color signals and video signals included in the scanning period of the television signal. On the other hand, the character signals included in the vertical blanking period are supplied through the character multiplex switching circuit 5 to the character signal decoder 6, where they are reproduced and output again through the character multiplex switching circuit 5 in the form of R, G, B signals. . Various operation keys are connected to the character signal decoder 6, and based on the operation of these operation keys, the manner in which the character signal is reproduced on the screen is determined, and the switching of the character multiplex switching circuit is also controlled. . 7 is an output amplification circuit for R, G, and B signals;
8 is a color cathode ray tube. The character signal decoder 6 may be formed separately from the color television receiver and connected to the color television receiver. 9 is a color encoder circuit provided according to the present invention,
10 is a matrix circuit which inputs the R, G, and B signals of character signals from the character multiplexing switching circuit 5 and outputs I, Q, and Y signals, respectively; 11 is a delay line for delaying the I signal; and 12 is an I signal. signal filter,
13 is an I modulation circuit, 14 is a Q signal filter, and 15 is a Q modulation circuit. Note that the I, Q modulation circuit 1
3 and 15 are balanced modulators. 16 is
This is a 3.58MHz oscillation circuit, and its output is applied to the I modulation circuit 13 through a -57° phase shifter 17, and the Q modulation circuit 15 through both a -57° phase shifter 17 and a -90° phase shifter 18. is supplied to The mixing circuit 20 combines the Y signal from the matrix circuit 10 and the synchronization signal from the synchronization signal generation circuit 19.
21 is a Y signal delay line, and 22 is an amplifier. 2
3 is a color burst signal generation circuit. The Y signal, I, Q modulation signals, and color burst signals are further outputted to an output terminal 25 via an amplifier 24. This output terminal 25 serves to supply teletext signals to the VTR. I signal filter 12 and Q in the color encoder circuit 9
The signal filter 14 is different from the normal I signal filter.
~1.5MHz, whereas the Q signal filter has a band of 0 to 0.5MHz, it is selected to have a considerably wide band, for example, 0 to 2.5MHz. Character signals R, G, B
The frequency band of the signal is very wide, so R, G, B
I,Q so as not to impair the fidelity of
This is because the signal filters 12 and 14 have a large band.

In the above circuit, R, G, and B signals, which are multiplexed character signals inputted to the color encoder circuit 9, are converted into I, Q, and Y signals by the matrix circuit 10. The I and Q signals are filtered by wideband filter 1.
After passing through 2, 14, I, Q modulation circuit 13, 1
5 and outputted via an amplifier 24 together with a Y signal and a color burst signal.

(f) Effects As described above, in the present invention, the signals input to the color encoder circuit 9 are created by the R, G, B signals from the multiplex switching circuit 5 of the television receiver, so the color CRT You can record the same image shown on 8 on a VTR.
Moreover, for that purpose, the color encoder circuit 9
It can be realized easily and inexpensively by simply adding .

Moreover, in the present invention, the bands of the I signal filter and the Q signal filter in the encoder circuit that modulates and outputs the reproduced character signal are made sufficiently wide, so that the R,
This is effective because G and B signals can be faithfully supplied to the VTR.

[Brief explanation of the drawing]

The figure is a block diagram of the main parts of a color television receiver embodying the present invention. 9...Color encoder circuit, 10...Matrix circuit, 12...I signal filter, 13...
I modulation circuit, 14...Q signal filter, 15...
Q modulation circuit.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a color television receiver for receiving teletext signals, a character multiplex switching circuit 5 that outputs R, G, and B signals in which character signals are multiplexed; From the switching circuit 5, the R, G,
an output amplification circuit 7 for amplifying the B signal; a color cathode ray tube 8 to which the output of the output amplification circuit 7 is input; and the R, G, B signals from the multiplex switching circuit 5.
A matrix circuit 10 which inputs a signal and outputs I, Q, and Y signals; an I signal filter 12 which receives the I signal and has a wide passband; and an I signal filter 12 which receives the Q signal and has a wide passband. The set Q signal filter 14 and the I signal filter 12 Q signal filter 14
I and Q modulation circuits 1 that respectively modulate signals from
3 and 15, and an amplifier 24 which receives the outputs of the I and Q modulation circuits 13 and 15 and the Y signal and outputs the signal to an output terminal 25. (2) The color television receiver according to claim 1, wherein the upper limit of the band of the I and Q signal filters 12 and 14 is approximately 2.5 MHz.