JPH02150185A - Television broadcast receiving circuit - Google Patents

Abstract

PURPOSE:To improve operability by executing an arithmetic processing for a desired television channel number, which has been selected and demodulated, with a constant, forming a channel selective signal obtained with allocating the supplementary information of the selected channel, and selecting the auxiliary channel by means of an auxiliary channel selecting circuit. CONSTITUTION:The television signal of the desired main channel selected by a main channel selecting circuit 1 is demodulated by a first demodulating circuit 3, and the channel number of the main channel is inputted to a channel selective signal preparing circuit 11. In the channel selective signal preparing circuit 11, the constant is operated, for example added, to the channel selecting number to form the auxiliary channel selective signal, which selects the auxiliary channel, it is added to an auxiliary channel selecting circuit 7, in the auxiliary channel selecting circuit 7, the auxiliary channel is automatically selected by the channel selective signal, and added to a second demodulating circuit 9. Thus, by interlocking to the selection of the main channel, the auxiliary channel can be automatically selected at high speed, and the operability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a television broadcast receiving circuit, and in particular to a television suitable for receiving high-definition television broadcasts that are broadcast while maintaining compatibility with current television broadcasts. Related to broadcast receiving circuits.

[Prior Art] In recent years, progress has been made in the development of high-definition television broadcasting that reproduces even the finest images clearly by widening the baseband frequency band and improving horizontal resolution.

Among such high-definition television broadcasts, a system that is compatible with the NTSC system is being considered so that it can be received by television receivers of the currently popular NTSC system.

In high-definition television broadcasting systems that are compatible with the NTSC system, signal components in bands that exceed the frequency band of the NTSC system cannot be transmitted within standardized individual television channels, so the following broadcasts are not possible. There are several possible methods.

In other words, as shown in Figure 4, each TV channel of the conventional NTSC system is used as the main channel, and the signal components (supplementary information) exceeding the main channel are assigned to an empty channel a certain distance from the main channel for supplementary purposes. In this method, the broadcasting station transmits the main and auxiliary channels, while the high-definition television receiver selects the auxiliary channels along with the main channels and processes the signals in combination.

For example, as shown in FIG. 5, a television broadcast receiving circuit that can support such a television broadcast system is such that a main channel selection circuit 1 selects the main channel of the received television signal, and a first demodulation circuit 3 selects the main channel of the received television signal. While demodulating and outputting the demodulated signal to the coupling circuit 5, the auxiliary channel selection circuit 7 selects an auxiliary channel from the same received TV signal added to the main channel selection circuit 1, and the second demodulation circuit 9 selects an auxiliary channel. The station signal is demodulated and output to the combining circuit 5, which combines the demodulated signal from the first demodulating circuit 3 and the demodulated signal from the second demodulating circuit 9, and performs subsequent video signal processing. It had a configuration that outputs to the circuit and synchronous signal processing circuit.

[Problems to be Solved by the Invention] However, in the television broadcast receiving circuit configured as described above, the main channel selection circuit 1 and the auxiliary channel selection circuit 7 are each configured independently, so that it is difficult to select individual broadcast channels. In addition to the main channel selection operation, multiple channel selection operations, such as the auxiliary channel selection operation, are required, making the channel selection operation extremely complicated.

The present invention has been made to solve these conventional drawbacks, and provides a television broadcast receiving circuit that is easy to perform high-speed automatic tuning of an auxiliary channel in conjunction with the selection of a main channel, and that is easy to operate and configured. The purpose is to provide.

[Means for Solving the Problems] In order to solve such problems, the present invention connects a first demodulation circuit to a main channel selection circuit that selects a desired television channel from a received television signal, and The channel selection circuit includes a channel selection signal that calculates a constant for the number of channels selected by the main channel selection circuit and selects an auxiliary channel to which at least video or audio supplementary information regarding the selected channel is assigned. An auxiliary channel selection circuit that outputs an auxiliary channel for the selected main channel is connected to the channel selection signal generation circuit, and an auxiliary channel selection circuit that selects an auxiliary channel from the received television signal using the channel selection signal. and a second demodulation circuit for demodulating the selected station signal is connected to this auxiliary tuning circuit.

[Function] In the present invention equipped with such means, the television signal of the desired main channel selected by the main channel selection circuit is demodulated by the first demodulation circuit, while the television signal of the desired main channel selected by the main channel selection circuit is demodulated by the first demodulation circuit. The number of channels is input to a channel selection signal generation circuit, and in this channel selection signal generation circuit, a constant is added to the number of channels selected by a calculation 1, for example, to form an auxiliary channel selection signal for selecting an auxiliary channel. In the auxiliary channel selection circuit, the auxiliary channel is automatically selected by the channel selection signal and added to the second demodulation circuit.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a television broadcast receiving circuit according to the present invention. Note that parts common to the conventional example are given the same reference numerals.

In the figure, a main channel selection circuit 1 selects a desired main channel from a received TV signal from a receiving antenna and converts it into a composite color TV intermediate frequency signal, and is connected to a first demodulation circuit 3 and a channel selection signal generation circuit. 11.

The first demodulation circuit 3 amplifies the composite color television intermediate frequency signal and performs, for example, AM detection, and outputs the detected wave signal to the coupling circuit 7.

The channel selection signal creation circuit 11 manually calculates the number of main channels selected by the main channel selection circuit 1, adds a constant M (for example, an integer 10) to calculate the number of auxiliary channels, and calculates the number of auxiliary channels. This generates a tuning signal for tuning and outputs it to the auxiliary tuning circuit 7.

Generally, TV channels are 1 to 69 channels or 2
Since there are 69 channels, the broadcasting station selects a constant in the range of integers 10 to 60 corresponding to the number of channel intervals between the main channel and the auxiliary channel to be transmitted, and performs the addition process.

The auxiliary channel selection circuit 7 inputs the received signal input to the main channel selection circuit 1, selects the hti auxiliary channel based on the channel selection signal, and performs frequency conversion, and is connected to the second demodulation circuit 9. ing.

In the auxiliary channel, signals such as video signal components that cannot be accommodated within the 1W range of the main channel of the NTSC system, PCM audio signals, and combination signals of these are stored as supplementary information in the auxiliary channel. It is what is sent.

The second demodulation circuit 9, like the first demodulation circuit 3, amplifies the selected station signal and performs, for example, AM detection, and the coupling circuit 5
It is connected to the.

As shown in FIG. 2, the coupling circuit 5 performs band compression on one line of the video signal of the test wave signal outputted from the first demodulation circuit 3 as shown by the disconnected line, while the second demodulation circuit Regarding the test wave signal output from 9, the auxiliary video signal for one line is divided into parts as shown in FIG. The latter half of the auxiliary video signal is coupled to the end of the compressed video signal shown in A in the figure to form a video signal for one line as shown in C in the figure and output to the subsequent stage.

The circuits after the coupling circuit 5 have a conventionally known circuit configuration, and include a color video processing circuit and a synchronization processing circuit.

In the present invention configured as described above, a received television signal from a receiving antenna is selected to a desired main channel by the main channel selection circuit 1, AM demodulated by the first demodulation circuit 3, and the detected wave signal is combined. On the other hand, the main channel number is added to the channel selection signal generation circuit 11 from the main channel selection circuit l.

The tuning signal creation circuit 11 calculates the number of auxiliary channels by adding a constant 10 to the number of selected main channels, and creates a tuning signal for tuning the auxiliary channel and sends it to the auxiliary tuning circuit 7. Output.

The auxiliary channel selection circuit 7 selects an auxiliary channel corresponding to the main channel based on the channel selection signal, and also performs frequency conversion.The second demodulation circuit 9 performs AM demodulation and outputs the demodulated signal to the coupling circuit 5.

In the coupling circuit 5, the first. While the test wave signal output from the second demodulation circuit 3 is compressed (see Fig. 2A), the F range of the test wave signal output from the second demodulation circuit 9 is compressed and the The video signals sent to FIG. 2 are combined before and after and output to the subsequent stage (FIG. 2C), where color video processing and audio processing are performed.

As shown in FIG. 3, a high-quality image is reproduced on a screen having an asbestos ratio of, for example, 16:9. In addition,
The shaded portion in FIG. 3 is the detected wave signal from the first demodulation circuit 3, and the other portions are the detected wave signal from the second demodulation circuit 9.

In the embodiment described above, the number of auxiliary channels is obtained by adding the constant "O" to the number of selected main channels, but the present invention is not limited to this.

For example, it can be calculated by multiplying the number of selected main channels by a constant 10, and in the present invention, the number of main channels is calculated using a preset constant.

It is sufficient to obtain the number of transmitted auxiliary channels.

Then, the channel selection signal generation circuit 11 may be arbitrarily configured according to the calculation process.

Note that each of the circuits described above can be connected directly or indirectly to the extent that their respective functions are not impaired.

[Effects of the Invention] As explained above, the present invention provides an auxiliary channel selection method in which a constant is applied to the number of selected and demodulated desired television channels and supplementary information of the selected channel is assigned. Since the configuration is such that the auxiliary channel is selected by the auxiliary channel selection circuit using this channel selection signal, automatic tuning of the auxiliary channel in conjunction with the main channel selection becomes easy and easy to operate. Improves sex.

Moreover, since the tuning signal can be generated by simply applying a constant to the number of channels to be selected, the selection of the auxiliary channel based on the selection of the main channel can be made faster, and the circuit configuration can be simplified. .

Therefore, the operability of the high-definition television receiver is improved for viewers, and it is possible to suppress the rise in the price of the receiver.

In particular, the present invention is suitable for a television broadcasting system in which each main channel and each auxiliary channel corresponding to the main channel are separated from each other by a fixed interval.

Note that the present invention is applicable not only to high-definition television receivers but also to NTSC
The present invention can be widely applied to television broadcast reception systems that are currently in practical use, in which arbitrary supplementary signal information such as a supplementary video signal or a PCM audio signal is added to and transmitted.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the television broadcast receiving circuit according to the present invention, FIGS. 2A to 2C are diagrams illustrating the connection relationship between the main channel and the auxiliary channel, and FIG. FIG. 4 is a diagram illustrating an example of the relationship between a main channel and an auxiliary channel, and FIG. 5 is a block diagram illustrating a conventional television broadcast receiving circuit. 1... ・Main channel selection circuit...First demodulation circuit...Coupling circuit/Auxiliary channel selection circuit...Second demodulation circuit...Tuition selection signal creation circuit

Claims (1)

[Claims] (1) A main channel selection circuit that selects a desired TV channel from a received TV signal, a first demodulation circuit that demodulates a selected channel signal from the main channel selection circuit, and a constant for the number of channels to be selected. a tuning signal generation circuit that calculates and outputs a tuning signal of an auxiliary channel to which at least video or audio supplementary information regarding the selected channel is assigned; 1. A television broadcast receiving circuit comprising: an auxiliary channel selection circuit that performs a channel selection; and a second demodulation circuit that demodulates a selected station signal selected by the auxiliary channel selection circuit.