RU2038697C1 - Device for suppression noise in receivers of wide band signals - Google Patents

Abstract

FIELD: radio engineering. SUBSTANCE: device has two subtracters 1 and 6, two multipliers 2 and 4, synchronous filter 5, decoupling unit 7, signal copy generator 8, regulated phase shifter 9, variable gain unit 10, delay line 11. EFFECT: increased functional capabilities. 1 dwg

Description

 The invention relates to radio engineering and may find application in communication systems with broadband signals.

 A multi-channel device for protection against narrow-band interference is known (Bokk O. F. Optimal characteristics of BZ filters against concentrated by spectrum interference. Communication equipment. Series TRS, 1987, issue 4, p. 81), in which the fight against narrow-band interference is carried out by the erase method channels affected by interference.

 The disadvantage of this device is the hardware complexity that increases with an increase in the base of the BSS, as well as the inability to turn it on at the output of the receiver, due to the need to use high-order filters in it. When using such devices, the input path of the receiver remains unprotected from narrowband interference.

 Narrowband jammers are also known, as described in ed. NN 438126, 1095419, 734681. Their disadvantage is the low noise immunity to narrowband interference.

 Closest to the technical nature of the proposed device is a device comprising a subtractor, a first multiplier, a signal copy generator, a notch filter, a second multiplier, a delay line, a phase-synchronous filter, and a first filter.

 An additive mixture of a broadband signal and quasi-harmonic interference arrives at the device’s input at the first input of the subtractor. At the output of the first multiplier, the broadband signal is converted to a narrow-band signal with a notch filter tuned to the frequency by multiplying with a copy of the modulating pseudorandom sequence generated by the signal copy generator. And the noise component, on the contrary, acquires additional modulation, due to which its spectrum becomes broadband and is practically not distorted by a notch filter. At the output of the second multiplier, the interference component is restored by secondary multiplication with a pseudo-random sequence. The delay line is necessary taking into account the signal delay in the notch filter and the first multiplier. Thus, at the output of the multiplier, the voltage with the interference frequency is restored. At the same time, there is no signal voltage, since the latter is filtered out by a notch filter. In the synchronous-phase filter, the reference for which is the restored interference voltage from the output of the multiplier, a copy of the interference voltage is restored. The latter, fed to the second input of the subtractor, provides compensation for interference in the received signal.

 The disadvantage of the prototype is the low noise immunity to narrowband interference.

 The drawing shows a noise suppression device.

 The device contains a series-connected first subtractor 1, the output of which is the output of the device, the first multiplier 2, a bandpass filter 3, an adjustable phase shifter 9, a second multiplier 4, a synchronous filter 5, a block 10 with an adjustable transmission coefficient, a second subtractor 6 and a decoupling device 7, the output which is connected to the second input of the first subtractor 1. The input of the device is connected to the first inputs of the subtractors 1 and 6. The output of the first subtractor 1 is connected to the second input of the synchronous filter 5. The output of the generator is 8 kopecks and a signal coupled to a second input of the first multiplier 2 and via the delay line 11 to a second input of the second multiplier 4.

 The input mixture containing the useful broadband signal and the narrowband interference simultaneously arrives at the first inputs of the subtractors 1 and 6. In the subtractor 6, the SHPS (SHPS *) estimate is subtracted from the input mixture, due to which the UE (UP *) estimate is formed at its output, which through the decoupling device 7 is fed to the second input of the subtractor 1, where it compensates for the narrow-band interference. As a result of compensation of the UE at the output of the subtractor 1, an NPS is formed, which is fed to the output of the device and simultaneously to the input of the multiplier 2, where it is multiplied with a synchronous reference signal coming from the output of the generator 8 of the copy of the signal. At the output of the multiplier 2, a narrow-band signal is allocated, which, after filtering in a band-pass filter 3, tuned to the middle frequency of the NPS spectrum (carrying the NPS), and an adjustable phase shifter 9 is fed to the first input of the multiplier 4. The reference signal from the output of the generator 8 is supplied to the second input of the multiplier 4 copies of the signal. Due to the manipulation according to the law of the reference bandwidth at the output of the multiplier 4, a BSS is formed, similar to a BSC at the input of the device. The adjustable phase shifter 9 provides the possibility of generating an estimate of the NWP (WB *) similar to that of the BW *, taking into account the delay of the narrow-band signal in the filter 3. The phase of the adjustable phase shifter 9 is adjusted so that the phase jumps in the estimation of the WB * are carried out at the same carrier phase values as and in the input signal.

 The SHPS from the output of the multiplier 4 is fed to the input of the synchronous filter 5, to the second input of which the SHPS from the output of the subtractor 1. As a result, the SHPS is formed at the output of the synchronous filter 5, the initial phase and the law of manipulation of which is determined by the initial phase and the law of manipulation of the SHPS at the output of the subtractor 1 Synchronous filter 5 provides not only the automatic adjustment of the phase of the NPS assessment under the input NPS, but also the automatic adjustment of the amplitude of the NPS assessment. From the output of the synchronous filter 5, the assessment of the BSS through block 10 is fed to the second input of the subtractor 6, where it compensates for the BSS from the input mixture. As a result, at the output of the subtractor 6, an estimate of the narrow-band interference is distinguished, which, through the decoupling device 7, is fed to the input of the subtractor 1, providing compensation for the narrow-band interference in the input mixture and the allocation of the BSS at the output of the subtractor 1.

 The block 10 and the delay line 11 are adjustable, provide compensation for the delay of the signal in the filter 3 and the phase shifter 9 and adjust the amplitude of the interference estimate. These blocks are used in individual cases and are not required.

Claims (1)

 INTERFERENCE SUPPRESSION DEVICE FOR WIDE-BAND SIGNAL RECEIVERS, comprising a first subtractor, a first multiplier and a bandpass filter connected in series, the first input of the first subtractor is a device input, a signal copy generator, the output of which is connected to the second input of the first multiplier and through the delay line to the first input of the second multiplier, the output of which is connected to the first input of the synchronous filter, characterized in that an adjustable phase shifter and a series-connected unit with adjustable transmission coefficient, a second subtractor and a decoupling device, the output of the bandpass filter through an adjustable phase shifter connected to the second input of the second multiplier, the output of the first multiplier connected to the second input of the synchronous filter, the output of which is connected to the input of the block with an adjustable transmission coefficient, the output of the decoupling device is connected to the second input of the first multiplier, the second input of the second multiplier is connected to the first input of the first multiplier.