SU1071976A1 - Signal-to-noise ratio measuring device - Google Patents

Description

The invention relates to a measurement technique and can be used to measure the signal-to-noise ratio of an additive mixture of signal and noise. radio communication systems.

A device is known comprising a controlled attenuator, a quad, a key, an integrator, a comparator, a counter with a state decoder, and a control unit til.

The drawback of the device is the limited range of measured signal-to-noise ratios when measuring only signals with known and fixed modality.

The closest technical solution to the invention is a device for measuring the signal-to-noise ratio, containing two keys, each with its output connected to the input of the corresponding accumulating meter of instantaneous power, the outputs of the latter are connected to the corresponding inverting and non-inverting input of the subtracting element output connected to the input of the threshold element, the output of the latter is connected to one of the inputs of two elements NOT, the second input of the first element is NOT connected to the output of the reference signal when the gate directly and, via the noise gate driver, to the second input of the second element, the outputs of the elements are NOT connected to the corresponding control inputs of the keys, the receiver's output output is connected to the input of both keys, the inverting input of the reading element is connected via the logarithmic converter to the inverting input of the second reading element, non-inverting input of which is connected to the output of the input block constants, the output of the second, subtractive element is connected to the input of the recording device C 23.

A disadvantage of the known device is the impossibility of measuring the signal-to-noise ratio with signals of the Continuous and pulsed structure with a priori unknown values of the input power.

The aim of the invention is to enhance the functionality of the device by measuring the signal-to-noise ratio with a priori unknown power values of continuous and pulse signals.

The goal is achieved by the fact that in a device for measuring the signal-to-noise ratio, containing two keys, each connected to the input of the corresponding instantaneous power accumulator, the outputs of the latter are connected to the corresponding inputs of the readout element, a logarithmic converter, the second subtraction element, the output of which connected to the vhstdom recording device, introduced a mixer, frequency-modulated local oscillator, band-pass filter, block

 control, four keys and two storage units, while the input terminal of the device through serially connected mixer and band-pass filter is connected to the inputs

10 of the first and second keys, the output I of the frequency-modulated local oscillator i is connected to the reference input of the mixer, the output of the first subtractive element is connected via a third key to

15 with the input of the logarithmic converter and with the output of the fourth key, the input connected to the output of the second accumulating instantaneous power meter, the output of the logarithmic converter is connected to the inputs of the fifth and sixth keys, the outputs of the latter through the corresponding first and second storage units are connected to the corresponding non-inverting and inverting the inputs of the subtracting element, the outputs of the control unit are connected to the corresponding control input of two accumulating meters of instantaneous power STI,

3Q six keys, two storage blocks and a frequency-modulated local oscillator.

FIG. 1 is a block diagram of the device in FIG. 2 - temporary

... device operation diagrams.

The device contains the investigated receiver 1, the output connected to the input of the mixer 2, the frequency-modulated local oscillator 3, the output connected to the reference. Input of the mixer 2,

0 bandpass filter 4 connected to the inputs of the first 5 and second 6 keys, the control inputs of which are connected to the second and third outputs of the control unit 7, accumulating meter 8 and 9 of instantaneous power, outputs connected to the corresponding inputs of the first subtractive element 10 whose output is connected to the input of the third key 11,

50 the fourth key 12, the output of which is connected by the output of the key 11 and with the input of the logarithmic converter 13, the fifth 14 and the sixth 15 keys, the first 16 and second 17 storing

55 blocks, the outputs connected to the respective inputs of the second subtractive element 18, the output of which is connected to the input of the recording device 19 and the input terminal 20 of the device 60;

Receiver 1 performs signal signals with a priori unknown power in the background of noise. The mixer 2 and the local oscillator 3 transform the spectrum received by the npHavjNICOM 1 signal with noise into the transmission frequency range of the band-pass filter 4. The first output of the control unit 7 serves to supply a modulating signal to the local oscillator 3, which provides for the detuning of the received noise signal for the band transparency bandpass filter 4.

Filter Band .f d -Af / -ro,

L ffo / 30 where l. - signal spectrum width

with angular modulation / fo - central frequency

filter 4.

The key 5 performs gating of the mixture of signal and noise, the key 6 - gating noise, in the case of detuning the frequency of the received mixture of signal and noise per band of transparency of the band-pass filter. Meter 8 provides a measurement of voltage, signal power level and noise PC Rc) g meter 9 - voltage equal to the power level Noise Rsh.

The device works as follows.

The first output of the control unit 7 generates a signal (Fig. 2a, which modulates the signal of the local oscillator 3, resulting in the output of the bandpass filter 4, the signal (Fig. 2S), the additive mixture of the signal and noise with the power level Thu + + RS The first key 5, controlled by a signal from the second output of control unit 7, ensures the passage of an additive mixture of signal and noise, which goes to the first meter 8 (Fig. 2b). The second key 6, controlled by a signal from the third output of control block 7, provides passing only the noise that by stumbles on the second gauge 9 (2g). The gauges B and 9 integrate the instantaneous power of the PC noise signal mixture. + P "i and the noise Psh. Respectively, the signal at the output of the first subtractive element 10 is equal to the difference (PC + Pf) - Rsch, t its level corresponds to the power of the PC signal. The output signal of the first subtractive element 10, corresponding to the signal power P through the third key 11, the logarithm converter 13, the fifth key 14 is fed to the input of the first storage unit 16. The signal from the output of the meter 9, according to the power P | t, h Through the fourth 12, the logarithm converter 13, the sixth key 15 is fed to the second memory unit 0 17. The signals received are proportional to the values GqPc and ftq Rc are subtracted on the second subtraction element 18, resulting in a sigma proportional to the logarithm of 5% C of the PC. - tq P y Cq-.

From the output of the second subtractive element 18, this signal is fed to the input of the instrument 19, which is registered, whose readings are proportional to the signal-to-noise ratio in decibels.

 The device provides signal / noise ratio measurements with a priori unknown continuous power and signal pulses. This is achieved 5 by parallel measurement of the instantaneous value of the signal power and noise and the possibility of frequency modulation of the local oscillator, i.e. detuning the signal from the band pass filter transparency.

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NIN them HI HI

FIG. 2

Claims (1)

‘(54X57) A DEVICE FOR MEASURING SIGNAL / NOISE RATIO, containing two keys, each with an output connected to the input of the corresponding accumulating instantaneous power meter, the outputs of the latter being connected to the corresponding inputs of the subtracting element, the logarithmic converter, the second subtract-. a measuring element, the output of which is connected to the input of the recording device, characterized in that, in order to expand the functionality of the device by measuring the signal-to-noise ratio for a priori unknown power values of continuous and pulsed signals, a mixer, a frequency-modulated local oscillator, a band-pass filter, are introduced into it a control unit, four keys and two memory blocks, while the input terminal of the device through a series-connected mixer and a bandpass filter is connected to the inputs of the first and second keys, the output of the frequency-modulated local oscillator is connected to the reference input of the mixer, the output of the first subtracting element through the third key is connected to the input of the logarithmic converter and to the output of the fourth key, the input connected to the output of the second accumulating instantaneous power meter, the output of the logarithmic converter is connected to the inputs of the fifth and sixth keys, the outputs of the latter through the corresponding first and second storage blocks are connected to the corresponding non-inverting and inverting inputs s second subtracter element, the control unit outputs are connected to the corresponding control input of the two collecting instantaneous power measuring devices, six keys, two memory blo