JP3013800U - Phase locked loop tuner tuning device - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To provide a phase locked loop tuner tuning device that can suppress an increase in component cost. In a phase-locked loop tuner tuning device 32 equipped with at least tuning means for tuning a receivable channel of a television broadcast by a phase-locked loop tuner section, a reference oscillation frequency signal 3 of the phase-locked loop tuner section is provided. ．
58 MHz is generated from the reference oscillation frequency signal of the oscillator for generating the reference oscillation frequency signal for frequency conversion of the reproduction system circuit for reproducing the image recorded on the recording medium.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a phase-locked loop tuner selection device for selecting a receivable channel of a television broadcast by a phase-locked loop tuner unit (also called a PLL tuner unit). In particular, it can be used for a video tape recording device, a video tape reproducing device, a video tape recording / reproducing device and the like.

[0002]

[Prior art]

 FIG. 4 shows a block diagram of a conventional phase locked loop tuner tuning device. Here, 31 is a microcomputer (hereinafter referred to as CPU) that controls the entire system, 32 is a PLL tuner unit that tunes to a selected reception channel, and 33 is a memory that stores the selected reception channel number. The PLL tuner unit 32 includes a tuner / IF unit 321 and a PLL circuit 322.

The PLL circuit 322 includes a band switch 325, an oscillator 326 that outputs a reference oscillation frequency signal of 4 MHz, a phase comparator 327, a low-pass filter 328, a prescaler 323, and a frequency divider 324. The tuner / IF unit 321 includes a tuner unit that receives a selected channel, a VCO 321a that functions as a part of the PLL circuit 322, an intermediate frequency amplification unit 321b, and an RF converter 321c. Since the tuner section, the intermediate frequency amplifying section 321b, and the RF converter 321c are high-frequency circuits, they are mounted and housed on a substrate integrated with the electromagnetic shielding chassis container. Reference numeral 34 is an antenna for receiving television radio waves transmitted from a broadcasting station. Reference numeral 35 is a video signal input terminal to the RF converter 321c.

[0004]

[Problems to be solved by the device]

 The conventional phase-locked loop tuner tuning device is configured as described above, and in particular, an expensive crystal oscillator is used for the oscillation unit 326 that outputs the reference oscillation frequency signal of 4 MHz in the PLL circuit 322. There were some problems that increased the cost of parts.

The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a phase locked loop tuner tuning device capable of suppressing an increase in component cost.

[0006]

[Means for Solving the Problems]

 The phase-locked loop tuner tuning device according to the present invention is the phase-locked loop tuner channel tuning device comprising at least tuning means for tuning a receivable channel of a television broadcast by a phase-locked loop tuner unit. The reference oscillation frequency signal of the phase locked loop tuner is generated from the reference oscillation frequency signal of the oscillator for generating the reference oscillation frequency signal for frequency conversion of the playback system circuit for playing back the video recorded on the recording medium. It is characterized by doing.

Further, the present invention provides a phase-locked loop tuner tuning device comprising at least a tuning means for tuning a receivable channel of a television broadcast by means of the phase-locked loop tuner section. The reference oscillation frequency signal is generated from a reference oscillation frequency signal of an oscillator for generating a reference oscillation frequency signal for frequency conversion of a recording system circuit for recording an image on the recording medium. In the present invention, the reference oscillation frequency signal of the oscillator is the reference oscillation frequency signal output of the oscillator that generates the reference oscillation frequency signal when performing frequency conversion on the output of the phase shift circuit of the video tape recording / reproducing circuit. It is characterized by Further, the present invention is characterized in that the phase-period loop tuner tuning device has a configuration in which an intermediate frequency amplifier and an RF converter are integrally arranged on a substrate together with the tuning means.

[0008]

[Action]

 The phase-locked loop tuner tuning device according to the present invention outputs the output of an oscillator for generating a reference oscillation frequency signal for frequency conversion in a reproduction system circuit for reproducing a video signal or a recording system circuit for recording the video signal. By using it instead of the reference oscillation frequency signal output of the oscillation unit of the phase-locked loop tuner unit, the oscillation unit of the conventional phase-locked loop tuner unit and the crystal oscillator used for the oscillation unit become unnecessary.

In addition, the phase locked loop tuner channel selecting device according to the present invention performs frequency conversion on the output of the phase shift circuit in the reproduction system circuit for reproducing the video signal or the recording system circuit for recording the video signal. When the reference oscillation frequency signal output of the oscillator for generating the reference oscillation frequency signal is used instead of the reference oscillation frequency signal output of the oscillation section of the conventional phase locked loop tuner section, the oscillation of the phase locked loop tuner section is generated. Further, the crystal oscillator used for the oscillation unit is unnecessary. Further, the phase-locked loop tuner tuning device according to the present invention has a configuration in which the intermediate-frequency amplifier and the RF converter are integrated together with the tuning means, as described above, the reference of the oscillator of the phase-locked loop tuner is used. The oscillation frequency output is input externally, eliminating the need for the conventional oscillator and crystal oscillator.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the phase-locked loop tuner tuning device of this embodiment. In FIG. 1, the same parts as those in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted. In the phase locked loop tuner channel selection device of the present embodiment, the PLL circuit 322 is not provided with an oscillating section for outputting a reference oscillation frequency signal of 4 MHz. That is, 3 output from the oscillator provided in the recording system circuit for recording the video signal shown in FIG. 2 on the video tape or the reproduction system circuit for reproducing the video signal shown in FIG. 3 from the video tape. A reference oscillation frequency signal of 0.58 MHz (in the case of VHS) is supplied to the PLL circuit 322.

In the recording system circuit for recording the video signal shown in FIG. 2, the 3.58 MHz color subcarrier extracted by the comb filter is amplitude-adjusted by ACC (Automatic Chroma Control), and burst signal amplitude is adjusted by burst emphasis. While the horizontal synchronizing signal is separated from the luminance signal and multiplied by 40, the phase shift circuit advances the phase by 90 degrees and converts the frequency. Since the reference oscillation frequency signal of 3.58 MHz is supplied from the oscillator 41 and frequency-converted to the frequency conversion circuit for this purpose, this reference oscillation frequency signal is used as the reference oscillation frequency signal of the PLL circuit 322.

In the reproduction system circuit shown in FIG. 3, a component of 630 KHz or higher of the reproduction color signal is blocked by a low-pass filter, the amplitude is adjusted, and then a frequency conversion of 3.85 MHz is performed. In this frequency conversion, the 3.58 MHz reference oscillation frequency signal output from the oscillator 42 is compared with the reproduction burst, and the deviation is used to control the 3.58 MHz voltage-controlled oscillator to reproduce the reproduction burst at 3.58 MHz. Since it is synchronized with the reference oscillation frequency, this reference oscillation frequency signal is used as the reference oscillation frequency signal of the PLL circuit 322.

The phase locked loop tuner channel selecting device of the present invention can be applied not only to the video tape recording / reproducing device but also to the video tape recording device and the video reproducing device.

[0014]

[Effect of device]

 As described above, according to the present invention, a reproducing system circuit for reproducing a video signal or a recording system circuit for recording a video signal is used instead of the reference oscillating frequency signal output of the oscillating section of the synchronous loop tuner section. Since the reference oscillation frequency signal output of the oscillator for generating the reference oscillation frequency signal for frequency conversion is used, the oscillation section of the phase locked loop tuner section and the crystal oscillator used in the oscillation section are unnecessary. Therefore, the cost of parts can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a phase locked loop tuner channel selecting device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a recording system circuit for recording a video signal.

FIG. 3 is a block diagram showing a configuration of a reproduction system circuit for reproducing a video signal.

FIG. 4 is a block diagram showing a configuration of a conventional phase locked loop tuner channel selection device.

[Explanation of symbols]

 31 Microcomputer (Channel Selection Means) 32 PLL Tuner Section 41, 42 Oscillator 321b Intermediate Frequency Amplifying Section 321c RF Converter 326 Oscillating Section 327 Phase Comparator

Claims (4)

[Scope of utility model registration request] 1. A phase-locked loop tuner tuning apparatus comprising at least tuning means for tuning a receivable channel of a television broadcast by a phase-locked loop tuner section, wherein a reference oscillation frequency signal of the phase-locked loop tuner section is provided. Is
A phase-locked loop tuner channel selection device, which is generated from a reference oscillation frequency signal of an oscillator for generating a reference oscillation frequency signal for frequency conversion of a reproduction system circuit for reproducing an image recorded on a recording medium. 2. A phase-locked loop tuner channel selection device comprising at least channel tuning means for tuning a receivable channel of a television broadcast by a phase-locked loop tuner section, wherein a reference oscillation frequency signal of the phase-locked loop tuner section is included. Is
A phase-locked loop tuner channel selection device, which is generated from a reference oscillation frequency signal of an oscillator for generating a reference oscillation frequency signal for frequency conversion of a recording system circuit for recording an image on the recording medium. 3. The reference oscillation frequency signal of the oscillator is a reference oscillation frequency signal output of an oscillator that generates a reference oscillation frequency signal when performing frequency conversion on the output of the phase shift circuit of the video tape recording / reproducing circuit. The phase-locked loop tuner tuning device according to claim 1 or 2. 4. The phase-period loop tuner tuning device has a configuration in which an intermediate frequency amplification unit and an RF converter are integrally disposed on a substrate together with the tuning unit. Alternatively, the phase-locked loop tuner tuning device described in 3 above.