JPS60198926A - Reception system for eliminating disturbing angular modulation wave - Google Patents

Abstract

PURPOSE:To eliminate a disturbing wave with no adjustment by demodulating a disturbing angular wave mixed in a reception signal wave, feeding back negatively the dem dulated signal to apply inverse modulation to the reception wave and forming the angular modulation wave into a band compression signal having a small frequency deviation thereby cancelling the modulation wave from the restored reception signal. CONSTITUTION:A local oscillation frequency of a VCO6 is multiplied with a reception signal from an input terminal 8 by a multiplier 11 to apply frequency conversion, the result is fed to a multiplier 2 via a BPF3, the inverse frequency conversion is applied by using the frequency of the VCO6 and the inputted angular modulation wave is restored by a BPF20. The modulation wave is demodulated by an FM detection circuit 5, its output controls the VCO6 to compress the band width of the modulated output wave and the inverse modulation output wave. The center frequency of the VCO6 is controlled by a center frequency control circuit 16 to apply the modulation output of the BPF3 to a subtractor 14 via a narrow band BPF18 and a level delay time adjusting circuit 13. Then the modulation wave at the same location extracted by a BPF12 is subtracted, the disturbing wave is fed to a multiplier 15 to eliminate the disturbing wave through cancellation.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention is directed to the prevention of interference by subjecting angular quality II4 such as frequency modulation or phase modulation to FM broadcast waves mixed into desired received signal waves such as television broadcast waves due to abnormal propagation. The present invention relates to an interference angle modulated wave prevention/reception method for removing waves, which is capable of almost completely removing interference angle modulated waves without substantially damaging desired received signal waves.

Prior Art Conventionally, in order to remove this kind of interfering angle modulated wave and receive a desired received signal wave, a notch filter has been used exclusively.

A reception method was used that uses sound to band-remove the main components of the interfering angle modulated wave. However, if the interfering angle modulated wave with a spread frequency band is sufficiently removed, the desired signal component within the same band will also be removed at the same time, resulting in secondary distortion in the received signal, and the overall had a drawback that resulted in a reduction in the quality of the received signal. In order to cancel out and eliminate only the interfering angle modulated wave without eliminating such desired signal components, the levels and phases of the antenna outputs from multiple antennas appropriately spaced are adjusted appropriately. Conventionally, a receiving method has been used in which a null point is provided in the antenna directivity by combining, and the direction of the null point is made to match the arrival direction of the interfering angle modulated wave. Since the direction of arrival of interfering angle modulated waves such as FM broadcast waves fluctuates, there is a drawback that the above-mentioned direction of the antenna null point must always be readjusted. Another drawback was that it would not be possible to fully deal with the situation if they arrived at the same time.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned conventional drawbacks, and to constantly transmit the interfering angle modulated wave to #1 without any adjustment, without causing any substantial damage to the desired received signal wave. ! The object of the present invention is to provide a receiving method for removing interference angle modulated waves that can be completely removed from received signal waves.

That is, the interference angle modulated wave removal reception method of the present invention actively receives and demodulates the interference angle modulated wave mixed into the received signal wave, and '41! ! The ll output is negatively fed back to perform inverse modulation on the entire received signal wave, and the interfering angle modulated wave is turned into a band-compressed signal with a small frequency deviation, which is canceled out and removed from the restored received signal. The received signal wave mixed with the wave is frequency-converted by the oscillation output of the voltage-controlled local oscillator to form first and second converted output waves, and the first converted output wave is converted to the frequency by the oscillation output of the voltage-controlled local oscillator. The oscillation output frequency of the voltage-controlled local oscillator is controlled by negative feedback of the detection output obtained by demodulating and detecting the inversely-converted output wave subjected to frequency inversion, and
The second conversion is performed by synthesizing the converted output wave with equal amplitude and antiphase to the second converted output wave through a filter whose pass band is a band near the carrier frequency of the interfering angle modulated wave. After the interference angle modulation wave component is canceled out and removed from the output wave □, the frequency of the output wave obtained by the cancellation and removal is inversely converted by the oscillation output of the voltage controlled local oscillator. (i'") It is characterized by being restored to the silkworm wave.

□ Note that restoration here refers to converting the frequency of the input signal using the same local oscillation output and then inversely converting it back to the original frequency.

EXAMPLES Below, the present invention will be described in detail by way of examples with reference to the drawings.

The jamming angle modulated wave removal reception method of the present invention first compresses the band of the jamming wave when removing the jamming angle modulated wave whose band has been expanded by modulating the jamming wave itself from the received signal. Even if deletion of the desired signal component occurs as a result of its removal, the band width in which the signal component deletion occurs is localized as much as possible, and then the interference wave in the narrow bandwidth is eliminated. Regarding band compression of angle modulated waves, which is the starting point of interference wave removal, the circuit system shown in FIG. 1 is conventionally known. In the angle modulated wave band compression circuit device having the configuration shown in the figure, an input angle modulated wave such as an FM broadcast wave is guided to a multiplier l, and multiplied by the oscillation output of the voltage controlled oscillator 6, thereby producing an oscillation output. is converted into a local oscillation, and the converted output of either the upper or lower sideband taken out via the bandpass filter 8 is led to the multiplier 2, and the same oscillation output as described above of the voltage controlled oscillator 6 is used as the local oscillation. A reverse frequency conversion to that described above is performed, and the input angle modulated wave is similarly restored via the band pass filter 20, and the angle modulated wave la limiter 4 and the FM detection circuit 5 which are restored by this frequency conversion and its inverse conversion are The demodulated output is negatively fed back to the voltage controlled oscillator 6 via the low-pass filter 7, and the demodulated output signal, therefore,
By changing the local oscillation frequency in accordance with the frequency shift of the input angle modulated wave, the bandwidths of the converted output wave and the inverse converted output wave obtained from multipliers 1 and 2 are compressed, and the negative feedback rate is reduced. By increasing the frequency, it is possible to localize only to the center carrier frequency component.

That is, in compressing the bandwidth determined by the frequency deviation Δf as the frequency t/i+Δ of the received input signal wave supplied to the input terminal 8, the oscillation frequency of the voltage controlled oscillator 6 is set to /, and the multiplier 1 If the frequencies of the conversion output and inverse conversion output of
+fB =f2 (2) The following relationship holds true. From these equations (11 and (2), -/i+Δf = /, (31). Therefore, the inverse conversion output frequency 18 of multiplier 2
is always equal to the reception input signal station wave number 11+Δf, regardless of the local oscillation frequency /, and the reception input signal wave is restored as the inverse conversion output. When the demodulated output of this restored received input signal wave is applied to the voltage-controlled excavator to perform local oscillation frequency /, 'ii: Negative feedback control, the feedback coefficient is set to α, and the range of change in the voltage-controlled oscillation frequency due to negative feedback control is Setting the center frequency at 1°, the local oscillation frequency fl is /, = fo + α·If (4). By substituting this equation (4) into equation (1) nine times and sorting it out, the following equation (6) is obtained.

(fl-f□) + (1-α)-If = f□(5
1. Therefore, when the feedback coefficient α=0, the frequency deviation Δf of the received input signal wave is directly passed through the bandpass filter 8.
Also, when the feedback body number α=1, the frequency deviation Δf of the received input signal wave is compressed and removed,
Only the converted output carrier frequency component is transmitted to the bandpass filter 8. That is, the carrier frequency fi of the received input signal wave is converted to the conversion output center frequency f□,
It will appear at the conversion output as a single carrier wave with no frequency deviation #, and therefore such an unmodulated carrier signal will appear at the output terminal IO.

In the interference angle modulated wave removal using the method of the present invention, the above-mentioned angle modulated wave band compression is applied to the interference angle modulated wave mixed into the received signal wave, and the interference wave is extracted as an unmodulated carrier wave. At the same time, the entire received signal wave is subjected to the same No. 46 processing to compress the interference wave mixed band, and by combining both signals with equal amplitude and antiphase, the interference wave that has been made into an unmodulated carrier wave is canceled out and removed1. Configure a receiving circuit for removing interference waves.

An example of the configuration of a receiving circuit for removing interference waves according to the method of the present invention is shown in I.
f Shown in Figure 2. In the circuit configuration shown in the second diagram, the circuit portion surrounded by a broken line frame is configured exactly the same as the circuit configuration shown in the first diagram. The wave is brought into the state of an unmodulated jamming carrier as described above with respect to FIG.

On the other hand, in the circuit configuration shown in the second diagram, the circuit portion added outside the dashed line frame performs the same signal processing on the entire received signal wave as described above, and then generates unmodulated interference carriers inside and outside the dashed line frame. The configuration is such that equal amplitude and antiphase are combined to cancel each other out.

The center frequency control circuit 16 connected to the voltage controlled oscillator 6 in the circuit portion within the broken line frame is: This is the circuit part. That is,
Guide the received input signal wave from the input terminal 8 to the multiplier 11,
Multiplication with the oscillation output of the voltage controlled oscillator 6 is performed, and frequency conversion is performed using the excavated output of the oscillator 6 as local oscillation.
The bandpass filter 12 extracts the conversion output of the side located in the same sideband as that within the broken line frame, and the subtraction circuit 14
, the interference wave component contained in the converted output is in the state of an unmodulated interference carrier wave, which is the same as the interference wave component taken out from the bandpass filter 8 within the broken line frame. A narrowband bandpass filter 18 whose pass band is only near the frequency of the unmodulated interfering carrier wave component within the broken line frame, and a level for correcting and removing differences in signal level and signal delay time inside and outside the broken line frame.

4 through the delay time adjustment circuit 18 and subtracted from the above-mentioned conversion output signal wave.
Performs cancellation and removal of interference waves. The converted output signal wave whose interference wave components have been canceled out in this way is guided to the multiplier 15,
Multiplier 1 by the same local oscillation from voltage controlled oscillator 6
1, and extracts an inversely converted output signal wave in the same band as the received input signal wave through a bandpass filter 17 and takes it out from an output terminal 19.

That is, the carrier frequency 'of the desired received input signal wave is
d, and the frequency of the interference wave is J + Δf as described above. When the feedback coefficient α = 1, the frequency 18 of the interference wave component in the conversion output of the multiplier 11 is equal to the frequency within the dashed line frame. The deviation Δf disappears, and the local oscillation frequency / is the center frequency f of its variation range. Therefore, /8=/1-10 (6). On the other hand, the received signal wave in the conversion output of the multiplier 11 is the result of the oscillation frequency 14 of the voltage controlled 0 oscillator 6 serving as local oscillation being subjected to negative feedback control by the interference wave demodulation output. On the contrary, it receives a frequency compliment with a frequency deviation Δf, and its frequency /d is /d'=(fd-Δf)−/. (7) becomes. Therefore, the interference wave frequency f in equation (6) is the terminal 1 within the broken line frame.
Since the frequency is the same as that of the unmodulated interfering carrier wave appearing at The interference wave of frequency 18 mixed in the converted output signal wave of
Only the converted output signal wave component of d' is obtained. The converted output signal wave component is guided to the multiplier 15 and frequency converted by local oscillation of the local 1 oscillation frequency fl = 10+Δf with α=1 in equation (4) from the voltage controlled oscillator 6, the equation Using (7), fd'+fl
”((fd-Δf)-10)+'(10+Δf) =
An inversely converted output signal wave with a frequency of fd(8) is obtained,
This means that the received input signal wave is completely restored except for mixed interference wave components. Note that the narrowband bandpass filter 18
is for extracting only the unchanged A14 interfering carrier wave as the V wave, so any narrow band pass filter can be used as long as the F leakage σ does not damage the amplitude information of the unmodulated interfering carrier wave. Filters may also be used.

I, if the carrier frequency j1 of the interference wave changes,
The center frequency control circuit 16 described above controls the oscillation frequency change range and center frequency of the voltage controlled oscillator 6 in response to changes in the interference wave frequency 11. By simply changing , the above-described interference cancellation and removal can be performed by following the change in the interference carrier frequency f1, while keeping the passband of the other bandpass filters fixed. I can do it.

Furthermore, the passband of the bandpass filter 8 within the dashed line frame is the same as the spectral distribution bandwidth of the interfering angle modulated wave t1, and the passband of the bandpass filter 12 outside the dashed line frame is obtained as the conversion output of the multiplier 11. It is sufficient to remove one of the unnecessary sideband components of the upper and lower sidebands centered around the local oscillation frequency 16 out of the signal band based on equation (7) of the frequency modulated received wave with frequency shift Δf. Depending on whether the upper or lower frequency conversion output sideband is used, a low-pass filter or a bypass filter can be used instead. It should be noted that if the phase shift caused by the narrow band pass filter 18, etc., which is considered to impede the cancellation and removal of interference waves, is corrected all at once by the level delay time adjustment circuit 18, there is no need to re-adjust fA from now on.

Next, by making the center frequency control circuit 16 in the configuration example shown in the second figure respond to the control information related to the interfering carrier frequency, it is possible to automatically follow changes in the interfering carrier frequency and achieve a state in which the mixed interfering wave component is zero. An example of a schematic configuration of a receiving circuit according to the present invention when converging to
As shown in the figure. The illustrated configuration example shows FM that has crossed the frequency allocation range and mixed into television broadcast waves due to abnormal propagation, etc.
It is configured to automatically remove interference from broadcast waves. That is, the beat frequency corresponds to the difference between the interference wave frequency included in the detected output video signal of the video detection circuit 21 in the television receiver connected to the restored received signal output terminal 19 in the configuration shown in the second diagram and the video carrier frequency. The component is detected by the beat detection circuit 28 which supplies the detected output video signal via the amplifier circuit 221. The beat detection circuit 28 is supplied with a synchronization signal separated and extracted by the synchronization separation circuit 24, which has supplied the video signal from the amplifier circuit 22, to detect an accurate synchronization signal that depends only on the interfering carrier frequency and is not affected by the video content. Detect the beat frequency in the synchronization signal section. Obtaining a voltage proportional to the beat frequency of the detection output and supplying it to the center frequency control circuit 16 described above,
Automatically controlling the center frequency 1° of the local oscillation frequency change range so that the frequency of the converted interfering carrier wave from multiplier 1 becomes a predetermined value regardless of the fluctuation of the beat frequency automatically tracks and removes the interfering wave. can be done.

In the configuration example shown in the second figure, for convenience of explanation, two frequency converters, multiplier l and multiplier 11, which are configured in exactly the same way and act in exactly the same way, are placed inside and outside the broken line frame. Although the stages are provided separately, it is of course possible to provide only one of the frequency conversion stages and to divide the conversion output between the inside and outside of the frame for use.

Effects As is clear from the above explanation, according to the present invention, the spectral distribution range of the interfering angle modulated wave mixed into the general received input signal wave is significantly localized, and ultimately it is converted into a single interfering carrier wave. Since the mixed interference wave is canceled out and removed by the extracted interference wave, compared to the case where the mixed interference signal Vt is canceled out using the original band, the desired (adverse effects on the i-wave component, such as phase distortion, etc.) are virtually ignored. It has the special effect of being able to eliminate interference waves by using the 4i11 circuit, which uses inexpensive circuit components and does not require any special precision adjustment.
The circuit device consisting of the above-mentioned circuit device can stably and reliably cancel out the interfering angle modulated waves.

In addition, when the reception method of the present invention is applied to remove FM broadcast waves mixed in the reception signal of television broadcast waves, the FM demodulated by the FM detection circuit 5 shown in Fig. 8rS1 is
The video signal component mixes into the M broadcast wave signal, degrading the 8/N of the demodulated heel broadcast wave signal, but since the interference wave to be canceled out is the angle modulated wave, such demodulation is not possible. The 8/N deterioration of the FM broadcast wave signal is reduced by the so-called lt'M improvement degree, and as the intensity of the interference wave increases, the degree of 8/N deterioration due to the video signal component is reduced.

Furthermore, by cascading multiple stages of interference angle modulation wave removal receiving circuits according to the method of the present invention, each corresponding to a different interference carrier wave frequency f, it is possible to reliably eliminate each of the multiple types of interference angle modulation wave noise mixed in the received signal wave. Furthermore, the center frequency f of the oscillation frequency variation range of the voltage controlled oscillator used as the local oscillator. If properly controlled, it is possible to automatically track and remove interfering angle modulated waves within a wide frequency range without adjustment, and it is possible to realize an automatic tracking and removal circuit device for interfering interfering waves.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of an angle modulated wave band compression circuit device which forms the basis of the interference angle modulated wave removal reception method of the present invention, and Fig. 2 is a detailed configuration of the interference angle modulated wave removal reception circuit according to the invention method. FIG. 8 is a block diagram showing an example, and FIG. 8 is a block diagram showing another example of the configuration of a part of the interference wave removal receiving circuit. 1, 2, 11, 15...multiplier, 8, 12
, 17 , 20... band pass filter, limiter, 5... FM detection circuit, 6... voltage controlled oscillator, 7... low pass filter, 8... input terminal, 9
, 10 , 19... Output terminal, l3/level/delay time adjustment circuit, 14... Subtraction circuit, 16... Center frequency control circuit, 18... Narrow band band pass filter, z
l...Video detection circuit, 22...Amplification circuit, 28...
・Beat detection circuit, c... synchronous separation circuit. Patent applicant: Japan Broadcasting Co., Ltd. 1.・Second! -] ■l'' 143rd Crystal Proceedings Amendment, April 27, 1980, 1. Display of the case Patent Application No. 54422 filed in 1980 Name of the invention Interfering angle modulated wave removal reception method 3, person making the amendment Relationship to the case Patent applicant (+36) Japan Broadcasting Corporation, 1. The scope of claims in the specification is amended as follows. [2. Claim L The received signal wave mixed with the interfering angle modulated wave is frequency-converted by the oscillation output of the voltage-controlled local oscillator, and the first and second . The first converted output wave is frequency-inverted by the oscillation output of the voltage controlled local oscillator, and the inversely converted output wave is demodulated and detected. The detected output obtained by demodulation detection is negatively fed back to control the voltage. After removing the oscillation output harmonic wave of the local oscillator, the output wave obtained by the removal is used as the oscillation of the voltage controlled local oscillator! An interference angle modulated wave removal reception method characterized in that the frequency is inversely converted by the output to restore a received signal wave in which the interference angle modulated wave is not mixed. Reception method. Harmonic rejection reception method. In the reception method according to claim 1, the center frequency of the oscillation frequency range of the voltage-controlled local oscillator that is subjected to negative feedback control by the detection output is determined by the carrier wave of the received signal wave and the interference angle modulated wave. 1. An interference angle modulation wave removal reception method characterized by performing negative feedback control according to a generated beat frequency. 2. "Offsetting elimination" on page 4, line 18 of the specification is corrected to "removal." 8, page 5, lines 5 to 11, “With that, -
- 1) to be amended as follows. [The occupied band of the interfering angle modulated wave is compressed, and a narrow band filter is used from the second converted output wave whose occupied band of the interfering angle modulated wave is compressed, and if necessary, the occupied band of the interfering angle modulated wave is compressed. 4. In "modulated wave removal" on page 9, line 9 of the same page, of"
In one embodiment of modulated wave removal, the following is corrected. 5. Correct "frequency conversion" in line 6 of page 18 to "inverse frequency conversion." 6. Corrected "of frequency modulated received wave" in line 9 of page 14 to "of frequency modulated received signal wave" and corrected "level delay time" in line 17 of the same page to "level/delay time". do. ,7. The following is added after line 14 of page 6 of the same No. 1. The mixed interference wave was canceled out by converting it into a single interference carrier and extracting it, but this method used a narrow band notch filter to remove the extremely localized spectrum distribution range mentioned above, and then , it may be supplied to the multiplier indicated by reference numeral 15 in FIG. 2 for inverse frequency conversion." Delete. 9. Corrected "cancellation removal" in lines 1, 2, 8, and 14 of page 17 to "removal," and replaced [for example, mutual distortion, etc.] in line 8 of page 17. Correct as shown below. [Particularly, when using the cancellation cancellation method as described in the above embodiment, phase distortion and damage to video signal components may occur.

Claims (1)

[Claims] L A received signal wave mixed with an interfering angle modulated wave is frequency-converted by the oscillation output of a voltage-controlled local oscillator to form first and second converted output waves, The frequency of the converted output wave is inversely converted by the oscillation output of the voltage controlled local oscillator, and the detected output obtained by demodulating and detecting the inverted output wave is subjected to negative feedback to control the oscillation 1...output frequency of the voltage controlled local oscillator. At the same time, the first f-converted output wave is equal-amplitude and anti-phase synthesized with the second converted output wave through a filter whose passband is a band near the carrier frequency of the interference angle modulated wave, thereby generating the second 1 from conversion Debaha...
After canceling and removing the interference angle modulated wave component described in DiJ, the frequency of the output wave obtained by the cancellation and removal is inversely converted by the oscillation output of the voltage controlled local oscillator to restore the received signal wave in which the interference angle modulated wave is not mixed. Disturbance characterized by what I tried to do! ... Harmful angle modulation wave removal reception method. 2. In the reception method according to claim 1, the center frequency of the oscillation frequency range of the voltage-controlled local oscillator that is subjected to negative feedback control by the detection output is determined by the carrier wave of the received signal wave and the interference angle modulated wave. An interfering angle modulated wave removal reception method characterized by performing negative feedback control according to the number of beat station waves generated.