SU1383219A1 - Spectrum analyzer - Google Patents

Abstract

This invention relates to a radio measuring technique. The spectrum analyzer, mainly sequential, contains a mixer 1, a frequency-modulated local oscillator 9, a sawtooth voltage generator 8, a narrowband path 2, a detector 3, analog-to-digital converters 4-6, an indicator 7, a digital control device 10, a comparator 11, delay device 12, resonant filter 13, phase detector 14, device 15 for sampling and storage, function-: transducer 16. The analyzer's speed is increased by minimizing the frequency intervals of the reversing sweep. 1 il. S

Description

Uo

with oo

00 GcE

The invention relates to a radio measuring technique, in particular, to a spectrum analyzer of a j-series action.

The purpose of the invention is to increase the analysis speed by minimizing the frequency intervals of the reverse sweep, and hence the frequency intervals in the sweep of the minimum speed.

The drawing shows a structural diagram of a spectrum analyzer.

The spectrum analyzer contains mixer 1, narrowband path 2, detector 3, analog-digital converters 4-6, indicator 7, sawtooth generator 8, frequency-modulated local oscillator 9, digital control device 1.0, comparator 11, delay device 12, resonant filter 13, phase detector 14, device 15 for sampling and storage, functional transducer 16.

Mixer 1, narrowband path 2 detector 3, analog-to-digital converter 4 and indicator 7 are connected in series.

The output of the sawtooth generator 8 is connected via analog-to-digital converter 5 with another input of the indicator. 7, and through the frequency-modulated local oscillator 9 - with the second input of the mixer 1. The digital control device 10 includes a communication interface 17 and a microcontroller 18 interconnected by address, data and control buses. The input of the communication interface 17 is connected via a comparator 11 to the output of the detector 3, and the outputs are connected to one directly and the other through the delay device 12 to the control inputs of the sawtooth voltage generator 8. The output of the narrowband path 2 is sequentially connected to a resonant filter 13, a phase detector 14, a sampling and storage device 15, a functional converter 16, an analog-digital converter 6, the output of which is connected to the second input of the communication interface 17, and a narrowband output The path 2 is also connected to the second input of the phase detector 14 .. The output of the delay device 12 is also connected to the control input of the sample and storage device 15 and the third input of the communication interface 17. Additional

the output of the communication interface 17 is connected to the control input of the device. 12 delays, and the fourth input - with the output of analog-digital converter 5.

The analyzer works as follows, I

In the initial state, when there is no signal at the output of the comparator, the frequency tuning frequency of the analyzer s / d ,, cc is increased compared to the optimal o (point used for accurate analysis tt

15

"Ms, cg. W / C, P2 / C

OPG

0

five

0

five

0

five

0

five

where C, are the proportionality coefficients depending on the allowable dynamic distortions in the search and analysis of signals and the shape of the amplitude-frequency characteristic of the narrowband path,

In the proposed analyzer, a five-point quartz filter was used as a narrowband path.

Frequency spacing required

,,. d.o

Scanning Reverse f -o-

The information parameter characterizing the tF Lee ratio (U with Signal Level; U is the detection level) at the time the signal is detected in the proposed analyzer is the phase difference between the signal voltages at the input and output of the resonant filter, which ultimately transforms into a code value at the output of an analog-to-digital converter (ADC) 6. Reading that the dependence lX d.6 on UC / UG is non-linear, to obtain a linear dependence of the interval of the reversal of the sweep on the value of the ADC code 6 in the proposed analyzer, it is used; Th converter.

The bandwidth of the resonant filter PF 7P is selected, based on the allowable displacement of the dynamic phase on the input and output of the resonant filter, less than 1.

At the moment when the signal increases the threshold of the comparator (detection level), the differential voltage of the comparator output through the communication interface starts a delay device, the output of which is generated. pulse duration ut, which leads to stopping the generator 8 sawtooth voltage (GPON). At this moment, the sampling device and the stored sample voltage of the phase detector, which, after functional conversion and conversion to a digital code in the ADC 6, is fed to the second input interface of the Digital Control Device. The digital control device reads data from the outputs A / D converters 5 and 6 and the calculation of the voltage value (Up) of the GPON (ADC code 5) to which it is necessary to reverse the sweep.

R

Up U4fp / 4f g ,,

where and is the current scan voltage of the GPON at the time of detection; and - full swing

sweep;

L.o5e- analyzer review band. The computation process is performed at 3 times At and for an applied microcontroller (MK-01) is several milliseconds, which is much less than the total gain in time provided by the proposed analyzer.

Upon termination of the pulse to the digital control device. switches GPON to reverse mode, which is produced until the voltage value (ADC code 5) reaches the calculated one. After the end of the sweep reversal. A pulse from the output of the digital control device triggers a delay device, the output voltage of which again stops the sweep for the time required to dampen the oscillations that may occur in the filter of the narrowband path during signal detection. The 4t 01 1 / P set-up time is determined by the bandwidth of the narrowband path and is set by the digital control device at the control input of the delay device. During the flto time, the digital control device sets the GPON scan rate equal to V spot and after the pulse finishes - delay delay sweep starts,

If the signal is not detected again in the 1.2Jfp frequency interval, the digital device records the code

five

five

0

50

0

ADC 5, after which the sweep speed is increased to a value of. In the case of repeated detection of a signal, the subsequent sweep should not overlap the last recorded ADC code 5. When the signal rins in interval 1, the sweep rate remains equal as long as sigia is present. .p comparator.

When the level of the HI signal at the comparator input becomes less than the set detection level, the control device records the ADC code 5 in the number pq.Boe, after which the sweep speed is increased to a value of c (kc

The effectiveness of the proposed analyzer depends on the degree of loading of the frequency dt aggazon frequency under study by the spectral components of the signals and the ratio of their levels. The increase in time of the proposed analyzer in comparison with the known one is achieved by reducing the interval width. the zone of inhibition, traversed at a rate of fl / opt B, is an average for different. analysis conditions win. over time, the ratio is about 1.5 times.

Claims (1)

Formula from found and A spectrum analyzer containing a mixer whose heterodyne input is connected via a frequency-modulated local oscillator to the output of a sawtooth voltage generator, and its output is via a serially connected narrowband path, the detector and the first analog-to-digital converter connected to one of the indicator inputs, the other input through which the second analog-to-digital converter is connected to the output of the saw-tooth generator, as well as to its control device, the first input JTOporo through the comparator n s. the detector output, the first output — with the first control input of the saw-voltage generator — and the second output through the delay device — with the second control input of the saw-voltage generator, which also in order to increase the analysis speed, it. consecutively included resonant filter, phase detector, sampling device and storage unit are entered. 513832196 function, the delay delay function is connected to the controller, the third analog-to-digital conversion input of the sampler, and the ramizer, the output of which is connected and the third digital input to the second input of the digital control and control device, the third output device, the output of which has a narrow aperture connected to the input of the control path is connected to the input of the delay device and the even filter and the second input to the output of the second anaphase detector, and output device-logo-digital converter.