JPH0553379U - Television signal demodulation circuit - Google Patents

Abstract

(57) [Summary] [Purpose] The reception category of the tuner is VHF LOW.
Also in the case of, the characteristics are set so that the inter-band station can receive well. [Constitution] The tuning voltage of the tuning tuner is detected by the tuning frequency detection circuit 1, and the broadcasting system of the demodulation circuit 2 is converted by this information.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a television signal demodulation circuit of a television receiver.

[0002]

[Prior Art]

 The broadcasting systems of the VHF LOW band and the VHF HI band in the television signal frequency band in France are different. In conventional television receivers, this difference in broadcasting system is used by a pre-selection microcomputer for pre-programmed signals, that is, VHF LOW signal, VHF HI signal, and broadcast system signal for independent selection of V HF LOW band. It controls the tuner and demodulation circuit.

FIG. 2 is a schematic block diagram of a conventional television signal demodulation circuit. In the figure, 1 is a tuner for selecting a television signal that converts a television signal from a general television broadcast frequency band to an intermediate frequency band, and 2 in the figure is a signal selection microcomputer that controls the signal converted to the intermediate frequency band. Demodulation circuit that demodulates video and audio signals by a broadcasting system according to the signal. In the figure, 3 is a channel selection microcomputer. Band switching of tuner 1 for television signal selection, switching of broadcasting system of demodulation circuit 2 To control.

[0004]

[Problems to be solved by the device]

 However, in the above-mentioned configuration, when the reception band of the tuner 1 for tuning is independent of V HF LOW and VHF HI, and the television broadcast spans the reception band of the tuner 1 for tuning ( * 1) Since the broadcasting system of the station in the VHF LOW reception band of the tuner 1 for tuning is different, that station cannot be viewed properly. (* 1 ... This corresponds to the interband in France) In view of such problems, the present invention aims to solve the drawbacks and enable good viewing of all stations in the interband.

[0005]

[Means for Solving the Problems]

 In order to solve the above problems, the television signal demodulation circuit of the present invention is provided with a tuning frequency detection circuit, and has a function of switching the broadcasting system of the demodulation circuit according to information from this.

[0006]

[Action]

 With the configuration described above, the present invention automatically switches the broadcasting system of the demodulation circuit when the tuning frequency detection circuit transmits information to the demodulation circuit. This allows good viewing of the entire interband.

[0007]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration according to an embodiment of the present idea. In FIG. 1, 1, 2, and 3 are the same as in FIG. Reference numeral 4 is a tuning frequency detection circuit for detecting the tuning voltage of the tuning tuner 1 and transmitting this information to the demodulation circuit 2.

The operation of the embodiment of the present invention configured as described above will be described below. When the VHF LOW band of the tuning tuner 1 is designated by the tuning microcomputer 3, and the frequency detected by the tuning frequency detection circuit 4 is in the inter-band, demodulation is performed by the information of the tuning frequency detection circuit 4. The circuit 2 converts the broadcasting system. For this reason, the inter-band can be favorably viewed even in the VHF LOW band of the tuner 1 for tuning.

[0009]

[Effect of the device]

 As described above, according to the television signal demodulation circuit of the present invention, even if the reception band of the tuner for tuning is VHF LOW or VHF HI and the band is interband, good viewing is possible in all interband stations. Is possible and its practical effect is great.

[Brief description of drawings]

FIG. 1 is a block diagram of a television signal demodulation circuit according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional television signal demodulation circuit.

[Explanation of symbols]

 1 Television signal tuning tuner 2 Demodulation circuit 3 Tuning microcomputer 4 Tuning frequency detection circuit

Claims (1)

[Scope of utility model registration request] 1. A tuner of a television receiver for tuning a television signal, a demodulation circuit, and a tuning frequency detection circuit, wherein the tuner for tuning a television signal detected by the tuning frequency detection circuit is selected. A television signal demodulation circuit, characterized in that the television signal demodulation system is switched by transmitting frequency information to the demodulation circuit.