SU1693727A1 - Device for reception of digital signals - Google Patents

Abstract

The invention relates to a technique for receiving discrete messages and can be used to ensure the noise immunity of digital radio communication systems. The purpose of the invention is to improve noise immunity. The device for receiving discrete signals contains an antenna 1, a wideband amplifier 2, mixers 3, synthesizers 4, a pseudorandom code generator 5, frequency-spaced channels consisting of a band-pass filter b, a reference frequency generator 7, a multiplier 8, a phase-rotation tel 9, an integrator 10, quadrant 11, adder 12, calculator 13 square root t of multiplier 14, nonlinear element 15 and multiplier 16, as well as comparison block 17, delay search block 18. The goal is achieved by introducing the quadr 19, the integrator 20, the adder 21, the inverter 22, the maximum value selection unit 23, the quadr 24, the signal divider 25 and the multiplier by two 26. In the latter, weighting factors are formed, which are fed to the inputs of the phases 14. According to with these weights, the multipliers 14 control the voltages of each signal element. In this case, the smaller the elemental signal-to-noise ratio, the less weight this ratio will be involved in the formation of the resulting signal-to-interference ratio at the output of the adders 16. 1 Il. i С /)

Description

The invention relates to techniques for receiving discrete messages and can be used to increase the noise immunity of digital radio communication systems.

The purpose of the invention is to increase noise immunity.

The drawing shows a structural electrical diagram of the proposed device.

The device for receiving discrete signals contains an antenna 1, a broadband amplifier 2, mixers 3, synthesizers 4, a pseudo-random code generator 5, frequency diversity channels consisting of a band-pass filter 6, a reference frequency generator 7, a multiplier 8, a phase shifter 9, an integrator 10, a square 11 , an adder 12, a square root calculator 13, a multiplier 14, a nonlinear element 15, and a multiplier 16, as well as a comparison unit 17, a delay search unit 18.

The goal is achieved by the introduction of a quadrator 19, an integrator 20, an adder 21, an inverter 22, a maximum value selection unit 23, a quadrator 24j of a signal divider 25, and a multiplier 26 by two.

The device operates as follows.

The inputs of block 23 from both channels receive voltages corresponding to either unity or zero. In this case, a voltage proportional to the maximum of the square of the envelope of the cross-correlation function between the received and reference signals is supplied to one input of block 23. At the other input of the block: 23, voltage is supplied proportionally. total interference variance. To assess the dispersion parameter, the voltage proportional to A _to / 2 from the output of block 23 is simultaneously supplied to the calculator 13 and to the inverter, which changes the sign of the voltage applied to it by -1. the input of the adder 21. Regardless of which of the information symbols (one or zero) is present at the output of the bandpass filters 6 at the input of the quadrator 19, there is always a mixture of signal with noise, and at the output of this additional qua Rathore 19 operates a voltage proportional to the square of the signal and interference. This voltage is supplied to an additional integrator 20, at the output of which, at the end of the Kth signal element, a voltage is generated proportional to the sum of the estimated noise variance and the square of the signal amplitude estimate.

At the output of the additional adder 21, a voltage proportional to the estimate of the interference variance in the Kth signal element acts. The voltage from the output of the adder 21 is supplied to the input of the divider 25, the second input of which is supplied with the voltage from the output of the computer 24, which is proportional to the estimate of the amplitude of the K-th signal element. At the output of the divider 25, a voltage is generated proportional to the amplitude estimate and inversely proportional to the variance estimate for each signal element, which in the multiplier 26 doubles. As a result, weighting factors are generated in the multiplier, which are fed to the inputs of the multiplier 14. In accordance with these weighting factors, the second multipliers 14 adaptively control the voltages of each signal element. Moreover, the smaller the signal-to-noise ratio, the less weight this ratio will participate in the formation of the resulting signal-to-noise ratios at the output of the 16 “adders.

Under the action of deliberate interference, striking with varying degrees the elements of the signal with frequency hopping, the proposed device provides an adaptive difference of discrete signals.

Claims (1)

Claim A device for receiving discrete signals, containing a series-connected antenna and a broadband amplifier, the output of which is connected to the input-coupled mixers, the heterodyne inputs of the mixers are connected to the outputs of the pseudo-random code generator (ISK), the outputs of the mixers are connected to the corresponding frequency-spaced channel, each of which consists of from a band-pass filter and series-connected sum-torus, quadrator, multiplier, non-linear element and multiplier, and t kzhe two subchannels executed as series-connected multiplier, an integrator and squarer ,. the quadrator outputs of the two subchannels $ 'are connected to the inputs of the adder of the frequency-spaced channels, and the inputs of the subchannel multipliers are combined and connected to the output of the band-pass filter of the frequency-spaced channels, the output of the reference frequency generator is directly connected to the heterodyne inputs of the resync-residents of the first subchannels, and to the heterodyne inputs of the second subchannels through a phase shifter, the outputs of the frequency diversity multiplier channels are connected to the inputs of the comparison unit, the clock input of which is connected to the inputs tegrarators of subchannels of frequency-spaced channels, an ISK generator and [a reference frequency generator, as well as an output of a delay search unit, the inputs of which are connected to the outputs of 25 non-linear elements of frequency-spaced channels, the output of a broadband amplifier, etc. I mean that, in order to increase noise immunity, the first quadrator, integrator, adder, signal divider, two multiplier, and also the maximum signal selection unit, the second quadrator and inverter are introduced in series, and the input of the first kva the speaker is connected to the outputs of the bandpass filters of the frequency-spaced channels, the outputs of the adders of the frequency-spaced channels are connected to the inputs of the maximum signal selection unit, the output of which is connected through the inverter to the second input of the adder, and through the second quadrator to the second input of the signal splitter, the output of the multiplier is connected to the second inputs of frequency diversity channel multipliers, the clock input of the maximum signal selection block is connected to the output of the delay search block and the Integrator reset inputs.