JPH0443771A - Disturbing wave eliminating device - Google Patents

Abstract

PURPOSE:To facilitate the mount of the device onto an existing television receiver while offering the use of an adaptor by detecting a frequency band when a disturbing wave detected for a blanking period of a received television receiver reaches a prescribed level or over and inserting a block filter so as to eliminate the wave. CONSTITUTION:A disturbing wave detection section 2 samples part of a blanking period of a received television signal branched from a disturbing wave elimination section 1 to extract only the disturbing wave and integrates the disturbing wave for a prescribed time and sends a control signal to a control section 3 when the level exceeds a prescribed level. In this case, the disturbing wave elimination section 1 consists of block filters NF1 - NF7 eliminating specified seven disturbing waves and analog switches SW1 - SW7 and the block filter NF is inserted by a command of the control section 3. The control section 3 applies insertion control of the block filters NF1 - NF7 in the elimination section and the control of the detection section 3. Thus, the constitution is simplified and the device is manufactured inexpensively and the device is used as an adaptor for a general home use television receiver.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to improving the reception of television radio waves, and in particular to a device for detecting and removing interference waves caused by foreign FM broadcast wave interference caused by Sporadic Eli delamination reflections. It is related to.

(Summary of the Invention) This invention relates to the removal of foreign radio interference waves using the Sporaden E layer of a general home television receiver. detect the intensity and
Based on this, one or more rejection filters are selected from a plurality of rejection filters having a predetermined rejection band and automatically inserted into the video signal pass circuit, and when no interference waves are detected, the video signal is passed as is. We provide an interference wave removal device that allows the waves to pass through.

As a result, it is possible to realize an inexpensive and efficient interference wave removal adapter device with a relatively simple configuration, and it is easy to install it in an existing television receiver.

(Prior Art) Conventionally, in a sporadic 8-layer interference wave (Es wave) removal device for television relay broadcasters and television broadcasting common listening facilities, detection and detection are performed in an intermediate frequency band obtained by converting the frequency of received radio waves. The equipment is complex and complex due to the fact that the removal process is performed, the interference wave detection is performed in a detection section that is independent of frequency screening and level detection, and the input and output of the equipment must be detected at the same time. Due to its high price, it was difficult to apply it to general home television receivers.

(Intelligence B to be Solved by the Invention) As mentioned in the section of the prior art, there is no conventional device for removing interference waves from the Sporadic 8 layer to television signals in a general home television receiver. It was complicated and expensive and difficult to apply as is.

SUMMARY OF THE INVENTION An object of the present invention is to provide an interference wave removal device that solves the above-mentioned problems, can be used as an adapter, and can be easily installed in an existing television receiver.

(Means for Solving the Problems) In order to achieve this object, the interference wave removal device of the present invention detects and eliminates interference waves superimposed on a television signal. comprises an interference wave detection section, an interference wave removal section, and a control section, and the interference wave detection section samples a part of the blanking period of the received television signal branched from the interference wave removal section and extracts only the interference waves. and a means for integrating the extracted interference waves for a predetermined time and sending a control signal to the control unit when the integrated value exceeds a predetermined level, the interference wave removal unit having a predetermined value. a plurality of rejection filters each having a rejection band and selectively inserted into the television signal pass circuit according to a control signal from the control unit; an analog switch driven by the control signal; a bypass circuit through which a signal should pass, and the control section includes a plurality of timing pulse generation circuits, a binary counter, a decoder, and a storage register for controlling the selection and insertion of the plurality of blocking filters in the removal section and controlling the detection section. and a switching circuit.

(Function) According to the interference wave removal device of the present invention, interference waves are detected during the blanking period of the received television signal, and when the detected interference waves reach a certain level or higher, the frequency band is detected. Then, a necessary blocking filter is selected from a plurality of blocking filters provided in advance and inserted into a video signal passing circuit to remove interference waves. Moreover, this operation is performed in the video frequency band. Therefore, it is possible to provide an interference wave removal device that has a relatively simple configuration and is highly efficient and can be applied in the form of an adapter to general home television receivers.

(Examples) The present invention will be described in detail below by way of examples with reference to the accompanying drawings.

FIG. 1 is a block diagram of a non-limiting embodiment of the present invention, and FIG. 2 is a timing relationship diagram of various pulse signals used in this embodiment.

According to FIG. 1, the interference wave removal device of the present invention has an interference wave removal unit
, an interference wave detection section 2 and a control section 3.

The interference wave detection unit 2 samples a part of the blanking period of the received television signal branched from the interference wave removal unit 1 and extracts only interference waves. This is integrated over a certain period of time, and when it exceeds a predetermined level, a control signal is sent to the control section 3.

In this case, the interference wave removal unit 1 includes a blocking filter NFI-NF7 that removes seven specific interference waves and an analog switch SWI.
- SW7, and the blocking filter NF is configured by the control section 3.
Inserted by the command.

It also has a bypass circuit 11 when no interference waves are present.

The control section 3 includes various timing pulse generation circuits 34, binary counters 37, decoders 35, storage registers 36, switching circuits 32, etc., and controls insertion of the rejection filter in the removal section and control of the detection section.

Next, the present invention will be explained in more detail with reference to FIGS. 1 and 2.

In the configuration shown in the first diagram, the received television signal applied from the input terminal is divided into three parts and delivered to the remover filter system 12, the remover bypass system 11, and the controller 3, respectively.

The interference wave removal circuit 12 is constructed by connecting blocking filters NFI to NF7 and analog switches SWI to SW7 in seven stages, and the seven blocking filters can be inserted in any combination according to a control signal. This removal circuit operates to detect interference waves during the sampling period, and removes interference waves during the non-sampling period.

In this embodiment, a bridge T-type LC filter is used as the blocking filter NF. The center frequency of this filter NF is the difference between the foreign FM frequency, which has the highest incidence of Es waves that occur every year, and the video carrier frequency of the domestic viewing TV channel, and the stop band is about 100 kHz.

On the other hand, the received television signal branched from the input and guided to the control section 3 is converted into only a synchronization signal by the synchronization separation circuit 31, and the timing pulse generation circuit 34 generates various signal pulses. As shown in Figure 2, these signal pulses include a sampling pulse P8 for extracting interference waves, a switching pulse PCM for time division control, a clock pulse PCK for the counter that sequentially controls the filter NF, and a reset pulse for resetting the integrating circuit. There are five types: P, and a strobe pulse PET that sets the register. Binary counter 37 increments with clock pulse P0 and sends a 3-bit binary signal pco to decoder 35 and storage register 36. This register 36 is latched at the timing of the strobe pulse according to the control signal from the detection section 2.

A switching signal is sequentially sent to the seven output lines of the decoder 35. The output of the decoder 35 and the output of the register 36 are switched by the switching circuit 32 according to the switching pulse PCH, and the analog switch SW of the removal circuit 12 is switched. Control. When the register is latched even at Ib1t, a switching signal is output to the OR circuit 33, SW8 of the through circuit 13 is turned on, and the video signal is switched from the bypass system to the system passing through the removal circuit.

The operation of the interference wave detection section 2 is as follows. Removal circuit 1
The video signal branched at the output of 2 enters the sampling circuit 21 of the detection section 2. Here, the sampling pulse Ps
(The period is ■=17-sec, V is the period of the vertical synchronization signal), and a part of the blanking period is sampled. This signal is rectified by a rectifying circuit 22, and then integrated by an integrating circuit 25 for a certain period of time (170 s). This signal is compared with a preset reference voltage in a comparator circuit 23, and if an interference wave occurs and exceeds a certain level, the comparator circuit 23
A detection output is generated from and sent to the register 36 of the control section 3. After being latched in the register, this integrating circuit is set by a reset pulse Pa (period: 10V).

The overall operation of this device will be explained in more detail below, divided into two periods: a sampling period and a non-sampling period.

During this period (a part of the blanking period), the filter NF is controlled so that only arbitrary frequency components pass through, and the interference wave level is detected and the frequency is determined. During this preparation period, the control section switching circuit 32 is switched to the decoder 35 side, and the decoder switches the removal section blocking filter NF.
Insertion is controlled.

When the first clock pulse PCII (period: 10V) arrives, a control signal is output to line 1 of the decoder at its falling point, and only the removal section switch SWI is turned off, and all other switches SW are turned on. Filters NF2-7 are inserted. At this time, if there is an interference wave corresponding to the filter NFI, the output of the integrating circuit 25 of the detection section increases, and when it exceeds a preset level, a detection signal is generated in the comparator 23. This signal is sent to the storage register 36, and the first register being addressed at this time is latched with a strobe pulse that is approximately at the same timing as the next clock pulse. Immediately thereafter, the integrating circuit 25 is reset, and at the same time, only the switch SW2 of the removal circuit is turned off, making it possible to detect only the interference waves corresponding to the filter NF2.

As described above, the detection operation is performed at each frequency with the period (IOV) of the clock pulse PCK, and the binary counter 37
storage register 3 depending on the presence or absence of interference waves.
6 is latched.

The basic operation during this period is as described above, but when the interference wave level is abnormally high or when interference waves other than waves E and E interfere, even the filter NF, which is not related to interference wave removal, may malfunction. To prevent this, decoder 3
Insert all filters NF on the 8th line of 5 outputs,
Malfunctions can be improved by integrating and holding the unnecessary waves at this time and adjusting the reference level of the comparison circuit.

During this sampling period (image and character signal portion), the control section switching circuit 32 is switched to the storage register 36 side, and the signal latched in the register is sent to the removal section analog switch circuit. That is, a blocking filter NF is inserted depending on the interference wave, and the interference wave is removed from the video signal.

In addition, in order to better understand the operating functions of the removing device of the present invention, FIG. 3 is a functional block diagram that extracts and shows only the main parts thereof, and the added reference numbers are the same as those in the first illustrated block diagram. The reference numbers are the same as those of blocks with corresponding functions. Which rejection filter in the rejection filter group 12 in FIG. 3 should be operated during the non-sampling period is as follows:
First, each blocking filter is sequentially designated by the sequential control pulse from the pulse generator 34 and the address designation signal, and whether or not the blocking filter should be operated during the non-sampling period is determined by the sampling 21 and the level sensor 23. That information is stored in memory group 36.

The above is a detailed explanation of the embodiment of the interference wave removal device of the present invention having the configuration shown in the first diagram. However, the present invention is not limited to this embodiment, and various modifications and changes may be made within the scope of the claims. will be obvious to those skilled in the art.

Finally, an experiment was conducted to remove interference waves using the apparatus configured as described in detail. The results are shown below.

In the experiment, a VHF signal generator was used instead of the interference wave.

■Interference wave removal characteristics When the interference wave is unmodulated, 35 to 4
FM change with the 0th order normal program that was able to attenuate by 0dB! It was found that there was an improvement of 20 to 30 dB when the interference was from a foreign FM broadcast station.

■Interference wave automatic removal characteristics Interference wave detection can be performed up to S/l-30dB,
The average time from generation of interference waves to initiation of removal operation was about 0.5 seconds.

(Effects of the Invention) As described in detail above, according to the interference wave removal device of the present invention, the frequency and intensity of interference waves that are expected to mix in the video frequency band during the blanking period of the received television signal Based on this, the necessary rejection filter is selected from among multiple rejection filters with a predetermined rejection band, and is inserted into the video signal pass circuit, so that television relaying is possible. Compared to conventional devices used in broadcasting stations, this device has the advantage of being simpler in structure, cheaper to manufacture, and usable as an adapter for general home television receivers.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 shows a configuration block diagram of an interference wave removal device according to an embodiment of the present invention, and FIG. 2 shows a timing relationship of various pulse signals used in this embodiment. FIG. 3 is a diagram for explaining the principle of the operating function of the removal device of the present invention. DESCRIPTION OF SYMBOLS 1... Interference wave removal section 2... Interference wave detection section 3 control section 11... Bypass system 12... Elimination circuit 13... Through circuit 21... Sampling circuit 22... Rectifier circuit 23...Comparison circuit 24...Switch 5W25...Integrator circuit 26...Hold circuit 31...Synchronization separation circuit 32...Switching circuit 33...OR circuit 34...Timing pulse generation circuit 35...Decoder 36...Storage register 37...Binary counter type-11

Claims (1)

[Claims] 1. An interference wave removal device that detects and removes interference waves superimposed on a television signal, the device comprising an interference wave detection section, an interference wave removal section, and a control section. , means for the interference wave detection section to sample a part of the blanking period of the received television signal branched from the interference wave removal section and extract only the interference waves, and for integrating the extracted interference waves for a predetermined time, means for sending a control signal to the control section when the integral value exceeds a predetermined level; a plurality of blocking filters selectively inserted into the pass circuit of the control unit, an analog switch driven by the control signal, and a bypass circuit for passing the video signal when no interfering waves are present; An interference wave removal device comprising a plurality of timing pulse generation circuits, a binary counter, a decoder, a storage register, and a switching circuit for controlling the selective insertion of the plurality of blocking filters in the removal section and controlling the detection section.