JPS6340498A - Adjacent interference measuring method - Google Patents

Abstract

PURPOSE:To reduce an error in a measured value, to contrive the increase of accuracy and to shorten a measuring time by electrically measuring a level in an interference by the use of a spectrum analyzer. CONSTITUTION:The output of a television signal generator 12 is set to the video carrier of a channel desired to be measured, a signal is outputted from a video signal generator 11 to modulate the video carrier, the 1.5MHz level of the cathode of a CRT is measured in the spectrum analyzer 18 to have a reference value. Then, the video signal is completely made black, a high frequency generator 13 is set to the video carrier of an adjacent channel, a high frequency signal generator 14 is set to a sound carrier to have a PS ratio to 6dB. While measuring the 1.5MHz component of the cathode 36 of the CRT by the spectrum analyzer 18, the level of the high frequency signal generators 13, 14 is changed. The output of the high frequency signal generator 13 at a point where the 1.5MHz component goes to -46dB to a reference level is obtained to make an output difference to the television signal generator 12 an adjacent interference ratio. This is sequentially measured while changing the output of the television signal generator 12.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for measuring adjacent interference in a television receiver.

(Prior Art) Conventionally, adjacent interference has been measured using a measuring device and a measuring method specified in JIS C6101.

The adjacent disturbance 111111 method will be described below with reference to the drawings. FIG. 4 shows the JTS 8111 standard. In FIG. 4, 42 and 43 are television signal generators that generate video carrier waves and audio carrier waves.

The video signal generator 41 outputs the color signal shown in FIG. 6, the video signal generator 44 outputs the color bar signal shown in FIG.
Each modulates a video carrier wave of a television signal generator 42,43. The outputs of the two television signal generators 42 and 43 are passed through a two-signal mixer 45 to the television receiver 4.
Enter 6.

In the constant force method, the television signal generator 42 is first tuned to a desired carrier wave. Next, the television signal generator 43 is tuned to the carrier wave of the adjacent channel. television receiver 46
In this step, the human power of the television signal generator 43 at the point where no interference is visually detected is determined, and the difference from the desired signal is taken as the adjacent interference ratio. This is done by sequentially changing the input to the television signal generator 42.

(Problems to be Solved by the Invention) However, with the above method, problems arise due to individual differences in the measurer, surrounding circumstances, etc. 11 There are many errors in the fixed values. Moreover, the measurement time was also long.

In view of the above-mentioned problems, the present invention aims to improve accuracy by reducing errors in measured values, and to shorten measurement time.

(Means for Solving the Problems) ``In order to solve the problems mentioned above, the adjacent interference of the present invention? 1
In the ill determination method, the level of interference is electrically measured using a spectrum analyzer.

Further, the detection limit is, for example, a point at which the interference level is -/16 dB with respect to the reference value.

(Function) The present invention achieves ? according to the above method. ll! This eliminates the l-determining error and shortens the measurement time.

(Example) An adjacent interference measuring method according to an example of the present invention will be described below with reference to the drawings. FIG. 1 is a wiring diagram of the device. High frequency signal generator 13.14 is 100K Hz~10
Frequency is variable up to 00 old 1z and output is 10dBm
Use one that is variable up to ~130 dBm. In addition, the spectrum analyzer 18 has a resolution up to +0011z, and a+! up to 100 old 1z! Use one that can be determined.

The measurement method is to mix the output signal of the television signal generator 12 and each output signal of the two high-frequency signal generators 13.14 using two two-signal mixers 15.16, as shown in FIG. input to the television receiver 17. The human input signal to the spectrum analyzer I8 is taken out from the cathode output terminal (green) 36 of the television receiver as shown in FIG.

First, match the output of the TV signal generator 12 to the video carrier wave of the channel to be measured, and output the signal shown in Figure 2 from the video signal generator 11.The modulation frequency is 1.5M Ilz.
) modulate the video carrier wave. Spec]・Rum analyzer 1
8, the 1.5 MHz level of the cathode 36 of the CRT is determined as a reference value. Next, the video signal is made completely black, the high frequency signal generator 13 is set to the video carrier wave of the adjacent channel, and the high frequency signal generator 14 is set to the audio carrier wave.
Set the ps ratio to 6dB. Spec 1 - Ram Analyzer 18
While measuring the 1.5 MHz components of the cathode 36 of the CRT, the levels of the high frequency signal generators 13 and 14 are varied (the ps ratio is maintained at 6 dB).

The output of the high frequency signal generator 13 at the point where the 1.5 old 1z component becomes 146 dFl with respect to the reference level is determined, and the output difference with the television signal generator 12 is taken as the adjacent interference ratio. This is sequentially measured while changing the output of the television signal generator 12.

As described above, according to this embodiment, by measuring the interference level with a spectrum analyzer, it is possible to improve the measurement accuracy and shorten the measurement time.

(Effects of the Invention) As described above, according to the present invention, by using a spectrum analyzer, (i) measurement accuracy can be improved, and (ii) measurement time can be shortened to 5% of the conventional one.

Therefore, its practical effects are great.

[Brief explanation of the drawing]

FIG. 1 is a wiring diagram of an adjacent interference measuring device in an embodiment of the present invention, and FIG. 2 is a signal waveform diagram of a video signal generator.
FIG. 3 is a block diagram for explaining measurement points,
Figure 4 shows the conventional measurement method (JIS C6]01)
FIG. 5 is a wiring diagram of the device in FIG. FIG. 6 is a conventionally used video signal waveform diagram. 11... Video signal generator, ]2... Television signal generator, 13.14... High frequency signal generator. 15, 16... 2 signal mixer, I7... TV receiver to be measured, 18... Spectrum analyzer. Patent applicant: Matsushita Electric Industrial Co., Ltd. Figure 1 Figure 3

Claims (1)

[Claims] A signal output of a television signal generator that generates a desired channel signal, a signal output of a first high-frequency signal generator that generates a video carrier wave for an adjacent channel, and a second high-frequency signal generator that generates an audio carrier wave for an adjacent channel. The mixed signal output is applied to the antenna input terminal of the TV receiver under test, and the cathode voltage waveform of the CRT is applied to the input terminal of the spectrum analyzer, and the video signal of the desired channel is output. 1. A method for measuring adjacent interference, comprising comparing adjacent interference output spectrum levels from the first and second adjacent channel high frequency signal generators using the spectrum level as a reference, and measuring based on the output level difference.