JPH077030B2 - Television interference wave measuring device - Google Patents

Description

The present invention relates to a device for measuring the frequency, intensity, etc. of an interference wave in a television reception channel band in a video signal band, and uses the device of the present invention. As a result, it is possible to measure and analyze various interference waves including interference due to the Sporadic E layer. Further, the method of the present invention can be used in a wide range of applications such as an interference countermeasure device.

(Prior Art) Regarding the measurement of the interference wave in the television reception channel band, there has conventionally been a method using a spectrum analyzer to analyze the frequency spectrum of a high-frequency signal, for example. I was discriminating while looking at the analyzer.

(Problems to be Solved by the Invention) The spectrum analysis of the interference wave in the high frequency signal in the conventional technique cannot be performed with high accuracy due to the influence of the video signal. Further, in the spectrum analysis of the demodulated video signal, highly accurate analysis cannot be performed due to the influence of the video signal, and it cannot be distinguished which of the upper and lower sidebands is mixed. Detection in the high frequency band is online and it is not possible to spend sufficient time for analysis and examination. There were drawbacks such as the inability to take an automatic viewing system.

Therefore, an object of the present invention is to provide a television interference wave measuring apparatus which eliminates the above-mentioned drawbacks and which can be automatically observed and analyzed off-line with a relatively simple structure and measuring principle.

(Means for Solving the Problems) In order to achieve this object, the measuring apparatus of the present invention is an apparatus for measuring an interference wave in a television reception channel band, and in demodulating a television signal, an upper sideband component and a lower sideband component are used. First means for performing synchronous detection by separating into waveband components, and interfering waves mixed in at least one horizontal scanning period of mutually different horizontal scanning periods within the vertical blanking period for each of the synchronously detected components The television is provided with a second means for sampling and extracting the signals, and a third means for A / D converting the sampled and extracted interference wave signals to perform high-speed Fourier transform spectrum analysis. It is characterized in that the interference waves respectively mixed in the upper sideband component and the lower sideband component of the signal are separated and spectrally analyzed.

(Example) The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the configuration of the observation receiving unit (a) and the observation analysis unit (b) of the measuring apparatus according to the present invention.

In the observation receiver shown in FIG. 1A, the observed high frequency input is down-converted by the receiver (tuner) 1.
Down-converted intermediate frequency signal (eg 58MHz
Band) is synchronously detected by the synchronous detectors 7, 8 and 9 via the Nyquist filters SAW and BPF3 for image quality monitoring, the upper sideband observation filters SAW and BPF4 and the lower sideband observation filters SAW and BPF5, respectively. Video signals V ₀ , V ₁ , V _{2 in the} frequency band are obtained.

SAW / BPF is a frequency band / band pass filter using surface acoustic waves, and their characteristics are SAW / BPF3, SAW / B
PF4 and SAW / BPF5 are shown in Fig. 2 (a),
The interference waves f ₁ , f ₂ , and f _{3 are shown in} comparison with each other in (b) and (c). FIG. 2 is described in the intermediate frequency signal band of the television, and frequencies f _V and f _{A in the} figure are carrier frequencies of video and audio, respectively.

The signals V ₀ , V ₁ , V ₂ obtained next are, for example, 10H, 11H, 12H, 13H (in the vertical blanking period of the signal V ₀ by using the switches 11 and 12 shown in FIG. 1A). 2 for odd fields
73H, 274H, 275H, 276H) signal V ₁ and signal V ₂ 10H,
A sample of 11H, 12H and 13H is interrupted (see Fig. 3). That is, the switch 11 samples and interrupts the signal V ₁ in the 12H and 13H periods of the signal V ₂ , and the switch 12 changes the signal V ₀ to the signal V _{1 in} the 10H and 11H periods.
The signal in the H period and the signal in the 12H and 13H periods of the signal V ₂ are sampled and interrupted. Thus, the interference wave measurement signal mixed in the upper sideband of the video signal on the same line of the video signal (the signal in the 10H and 11H periods of the signal V ₁ ), the interference wave measurement mixed in the lower sideband of the video signal Signal (signal V ₂ said 12H, 13
It is possible to carry an H period signal) and an image quality monitoring signal (signal V ₀ ).

Further, in preparation for the case where the television signal which has been subjected to interference interference has a synchronization disturbance due to interference interference, a synchronization signal of a television signal of a peripheral other station radio wave having a synchronization signal having the same timing as the television signal. For resynchronization, the circuit configuration of the receiver (tuner) 2, SAW / BPF 6, sync detector 10, sync separators 14, 15, phase comparison adjuster 16, regenerative sync generator 17 and switch 13 is shown in FIG. (A) It is added to the observation receiver shown. Thus a series of surveillance,
The measurement signal is temporarily recorded in VTR18 for offline observation.

Next, in the observation and analysis unit shown in Fig. 1 (b), once the VTR1
The video signal for observation recorded in 8 is distributed to the A / D converter 19 and the gate pulse generator 20. Gate pulse generator
In the case of 20, the signal A /
The trigger pulse for D conversion is generated. The digital signal output obtained by this is transferred to the CPU 21 in real time, spectrum analysis is performed by the FFT board 22, the data is stored in DISCI3, and if necessary, this spectrum analysis data is processed again by the CPU 22 and the printer is processed. 2
Output at 4 to obtain interference disturbance information. As described above, automatic measurement analysis can be performed offline.

In addition to the method of measuring using the three outputs of the signals V ₀ , V ₁ and V ₂ as described above, it is also possible to measure the interference wave with only the two outputs of the signals V ₀ and V ₂ . In this case, the circuit is simplified. That is, the interference waves of the upper sideband and the lower sideband are simultaneously mixed in the signal V _0. Of these, the signal V 0 is output using the lower sideband interference wave information from the output of the signal V _2. The lower sideband interference wave in ₀ can be separated. Therefore, the interference wave mixed in the upper sideband and the interference wave mixed in the lower sideband can be separately measured by, for example, software processing by the CPU 22 described above.

Symbols 31 and 32 in FIG. 3 indicate a color burst signal and a character information signal, respectively.

(Effects of the Invention) As described above, by using the measuring apparatus of the present invention, the interference wave in the television reception channel band can be accurately measured without being affected by the video signal component (D / U = 50d).
(Up to about B), it is possible to distinguish which of the upper and lower sidebands the interference waves are mixed in in the video band, and it is possible to easily and accurately measure and analyze offline.

[Brief description of drawings]

FIG. 1 shows a block diagram of the configuration of the observation receiving section (a) and the observation analysis section (b) of the measurement apparatus embodiment of the present invention, and FIGS. 2 (a), (b) and (c) are SAWs, respectively.・ BPF3,4,
5 shows the passage characteristic, and FIG. 3 shows a part of the signal in the vertical blanking period of the television signal. 1,2… Receiver (tuner) 3,4,5,6… SAW / BPF 7,8,9,10… Synchronous detector 11,12,13… Switch, 14,15… Synchronous separator 16… Phase comparison Adjuster, 17 ... Playback synchronization generator 18 ... VTR, 19 ... A / D converter 20 ... Gate pulse generator, 21 ... CPU 22 ... FFT board, 23 ... DISC 24 ... Printer, 31 ... Color burst signal 32 ... Character Information signal

Claims (2)

[Claims] 1. An apparatus for measuring an interference wave in a television reception channel band, comprising first means for separating and coherently detecting an upper sideband component and a lower sideband component in demodulating a television signal, Second means for sampling and extracting interference wave signals mixed in at least one horizontal scanning period of mutually different horizontal scanning periods within the vertical blanking period for each of the synchronously detected components; The respective interference signal extracted by
Third means for performing D-conversion and high-speed Fourier transform spectrum analysis, and separating the spectrum analysis by separating the interference waves mixed respectively in the upper sideband component and the lower sideband component of the television signal. Television interference wave measuring device characterized by. 2. The measuring device according to claim 1, wherein when the television signal is accompanied by a disturbance of synchronization due to interference, the erroneous detection of a predetermined sample position due to the disturbance of synchronization is performed. The second means comprises means for resynchronizing with a synchronizing signal of a television signal of a peripheral other station having a synchronizing signal having the same timing as the television signal subjected to interference interference. Interference wave measuring device.