JP3019106U - Adjustment device for television AGC circuit or AFT circuit - Google Patents

Abstract

(57) [Abstract] [Purpose] It is not necessary to prepare a measuring instrument in order to adjust the AGC circuit or AFC circuit of the television, and the test point to which the measuring instrument is connected can be abolished. Workability of these adjustments will be improved. [Configuration] AGC output terminal of AGC circuit 15 or AFT
The AFT output terminal of the circuit 14 is connected to the input port of the microcomputer 4, and when the microcomputer 4 is operated in the AGC adjustment or AFT adjustment mode,
The adjustment state of AGC adjustment or AFT adjustment is displayed on the CRT 8 on-screen.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a device for adjusting an AGC circuit for automatically adjusting an operation gain of a tuner for selecting a radio wave of a television or an AFT circuit for automatically adjusting a tuning frequency in the tuner.

[0002]

[Prior art]

 Conventionally, adjustment of an automatic gain control (AGC) circuit or an automatic frequency tuning (AFT) circuit of a television is performed by connecting a measuring instrument such as an oscilloscope to the adjustment test point of the AGC circuit or the AFT circuit on the television production line. , While operating the AGC circuit or AFT circuit adjustment unit while monitoring the display.

[0003]

[Problems to be solved by the device]

 However, in the conventional method for adjusting the AGC circuit or the AFT circuit as described above, it is necessary to provide a test point for connecting the measuring instrument, and it is necessary to prepare the measuring instrument in the production line. It took time and effort to connect the measuring instrument to each test point, resulting in poor workability and inconvenience. The present invention has been made to solve the above-mentioned problems, and it is possible to eliminate the test point to which the measuring instrument is connected for adjusting the AGC circuit or the AFT circuit of the television. It is not necessary to prepare a measuring instrument on the production line, and the adjustment status of AGC or AFT can be displayed on-screen on the CRT of the TV and adjusted while monitoring it. It is an object of the present invention to provide a circuit or an AFT circuit adjusting device.

[0004]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the invention of claim 1 is an AGC circuit for automatically adjusting an operation gain of a tuner for selecting a radio wave of a television or an adjusting device for an AFT circuit for automatically adjusting a tuning frequency in the tuner, AGC adjusting unit or AFT adjusting unit provided in the AGC circuit or AFT circuit, a signal processing circuit that processes the signal of the channel selected by the tuner, a microcomputer that controls the operation of the signal processing circuit, and a signal A CRT that displays an image processed by the processing circuit, and the AGC output terminal of the AGC circuit or the AFT output terminal of the AFT circuit is connected to the input port of the microcomputer, and the microcomputer performs AGC adjustment or AFT. When operating in the adjustment mode, the adjustment status of AGC adjustment or AFT adjustment is on-screen to the CRT. In which it was to be down display. According to a second aspect of the present invention, in the television AGC or AFT adjustment apparatus according to the first aspect, in the operation in the adjustment mode, the adjustment voltage of the AGC output terminal of the AGC circuit or the AFT output terminal of the AFT circuit is CRT. The bar is displayed along with the adjusted voltage value.

[0005]

[Action]

 In the adjusting device for the AGC circuit or AFT circuit of the television of the present invention having the above-mentioned configuration, the AGC output of the AGC circuit or the AFT output of the AFT circuit is input to the microcomputer, and the microcomputer is controlled to perform the AGC adjustment or AFT. When operated in the adjustment mode, the adjustment voltage for AGC adjustment or AFT adjustment is displayed on-screen on the CRT. Therefore, AGC adjustment or AFT adjustment can be performed while monitoring the on-screen display without preparing a measuring instrument.

[0006]

【Example】

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block configuration diagram of a television. The television 1 includes a tuner 2 that tunes a television broadcast wave, a signal processing circuit 3 that is a one-chip IC that amplifies and detects the video and audio signals of the channel tuned by the tuner 2, a signal processing circuit 3, and the like. , A horizontal deflection output circuit 5, a vertical deflection output circuit 6, a sound output circuit 7, a CRT 8 for displaying a television image, a speaker 9 for outputting sound, etc. Composed of.

The microcomputer 4 receives a user operation signal from the remote control light emitting unit 10 and operates in a predetermined mode. The signal processing circuit 3 includes a first intermediate frequency amplifier circuit (PIF) 12 that receives an intermediate frequency signal from the tuner 2 through a SAW filter 11, a second intermediate frequency amplifier circuit (SIF) 13, and automatic frequency tuning (AFT). It has a circuit 14, an RF AGC circuit 15 as an automatic gain control (AGC) circuit, and a video signal circuit 16 for detecting and demodulating a video signal and generating outputs for horizontal and vertical deflection.

The AFT circuit 14 has an AFT adjusting unit 17 that can change the inductance of the coil, and a terminal (AFT output terminal) that outputs a voltage to be adjusted. Further, the RFAGC circuit 15 is an AGC adjusting unit that includes a semi-fixed resistor. It has a section 18 and a terminal (AGC output terminal) for outputting the adjusted voltage to the tuner 2. These AFT output terminal and AGC output terminal have been conventionally derived as test points for connecting a measuring instrument in order to adjust them in a television production line. Are connected to the AFT input port A / D2 and the AGC input port A / D1 of the microcomputer 4. Specifically, the divided voltage of the series resistance connected between each terminal and the ground is given to each input port of the microcomputer 4. The microcomputer 4 A / D converts the voltage and takes it in.

The microcomputer 4 operates in a predetermined mode by an operation from the remote control light emitting unit 10, and when a mode for performing AGC adjustment or AFT adjustment is selected, an AGC output terminal of the RF AGC circuit 15 or an AFT circuit of the AFT circuit 14 is selected. Each adjustment voltage (adjustment voltage value and bar display) of the output terminal is configured to be displayed on-screen on the CRT 8. It should be noted that during normal television broadcast reception, television images are displayed on the CRT 8 by the operations of the tuner 2, the signal processing circuit 3, the microcomputer 4, and the like.

The AGC adjustment or AFT adjustment operation of the television 1 of the present embodiment configured as described above will be described. When the operator operates the AGC adjustment unit 18 or the AFT adjustment unit 17 to perform the AGC adjustment or the AFT adjustment in a state in which the mode for performing the AGC adjustment or the AFT adjustment is selected, the AGC output terminal or the AFT output is correspondingly output. Each adjustment voltage of the terminal changes, which changes the on-screen display of the CRT8.

2A and 2B show the display screen of the CRT 8 in each adjustment mode, and the adjustment state at that time is displayed by the voltage value and the level position (black mark) in the bar display. Appropriate AGC voltage and AFT voltage are determined according to the model, and the operator adjusts them while monitoring the CRT 8 so that they are the values. Therefore, unlike the conventional method, it is not necessary to connect a measuring instrument to each test point of the AGC or AFT to make adjustments, and it is not necessary to prepare a measuring instrument, improving workability and improving the test point. Can be abolished.

The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. For example, for the on-screen display of the CRT8, AGC adjustment and AFT adjustment are shown as separate screens, but other adjustments are possible, and multiple information items including those adjustment states are displayed on the monitor at the same time. You may

[0013]

[Effect of device]

 As described above, according to the television AGC circuit or AFT circuit adjustment apparatus of the present invention, each adjustment state is displayed on-screen on the television CRT in the AGC adjustment or AFT adjustment mode. Adjustment work can be performed while monitoring, and the labor of preparing and connecting measuring instruments to adjust them on the production line can be saved, workability can be improved, and the test points to which the measuring instruments are connected are eliminated. It becomes possible.

[Brief description of drawings]

FIG. 1 is a block diagram of an adjusting device for an AGC circuit or an AFT circuit of a television according to an embodiment of the present invention.

2A and 2B are diagrams showing a CRT display screen according to the present embodiment.

[Explanation of symbols]

 1 Television 2 Tuner 3 Signal Processing Circuit 4 Microcomputer 8 CRT 14 Automatic Frequency Tuning (AFT) Circuit 15 Automatic Gain Control (AGC) Circuit 17 AFT Adjusting Section 18 AGC Adjusting Section

Claims (2)

[Scope of utility model registration request] 1. An AGC circuit for automatically adjusting an operation gain of a tuner for selecting a radio wave of a television or an AFT circuit adjusting device for automatically adjusting a tuning frequency in the tuner, the AGC circuit or the AGC provided in the AFT circuit. An adjusting unit or an AFT adjusting unit, a signal processing circuit that processes a signal of a channel selected by a tuner, a microcomputer that controls the operation of the signal processing circuit, and an image processed by the signal processing circuit is displayed. And a CRT, and an AGC output terminal of the AGC circuit or an AF of the AFT circuit.
The T output terminal is connected to the input port of the microcomputer, and when the microcomputer is operated in the AGC adjustment or AFT adjustment mode, the adjustment state of AGC adjustment or AFT adjustment is displayed on-screen on the CRT. An adjusting device for an AGC circuit or an AFT circuit of a television characterized in that 2. In the operation in the adjustment mode, the adjustment voltage of the AGC output terminal of the AGC circuit or the AFT output terminal of the AFT circuit is bar-displayed on the CRT together with the adjustment voltage value. Item 1. A television AGC circuit or AFT circuit adjustment device according to item 1.