SU1649635A1 - Random-signal generator - Google Patents

Abstract

The invention relates to radio engineering and communications. The purpose of the invention is to reduce the level of out-of-band spectrum components. The pulses from the reference generator 1 are fed to a controlled frequency divider 2, which reduces their frequency by N times, and then to counter 3. Using a serially connected frequency divider 7, a random number generator 8 and a code converter 9, a code is generated that controls the division factor divider 2, so that n predetermined frequencies can be generated. When the 3 counter is filled, the numbers at the outputs of the 4-code converter change according to a certain law. Next, the D / A converter 5 converts this digital signal to an analog one, and the low-pass filter 6 eliminates the constant component and smoothes the stepped nature of the voltage. The former allows one to form output oscillations of any shape and promptly change the structure of random signals. 2 Il.

Description

The invention relates to radio engineering and communications and can be used in the study of noise immunity of radio systems.

The purpose of the invention is to reduce the level of out-of-band components of the spectrum.

Figure 1 shows a structural electrical circuit of a random signal generator; 2 shows graphs explaining the operation of the device.

The random signal generator contains a reference oscillator 1, a controlled frequency divider 2 (UDCH), counter 3, the first converter 4 codes, a digital-to-analog converter (DAC) 5, a low-pass filter 6, a frequency divider 7, a random number generator 8 (RNG), the second converter code 9.

The shaper random signals works as follows

The sonor generator 1 receives pulses with a frequency for for the input of the UDCH 2, at the output of which the pulse frequency decreases by NI times, where NI is the division factor, the code of which is set at the outputs of the second code converter 9.

Pulses from the output of UDCH 2 arrive at counter 3, the capacity of which is chosen equal to Ketch, and through a frequency divider 7 with a division factor of Kdch to the clock input of the RNG 8. After every Ketch KDH pulses, a signal from the output of the divider 7 at the RNG 8 outputs sets a new code equal numbers from 0 to n-1. A certain number i at the input of the second code converter 9 corresponds to the number NI at its output, which determines the pulse frequency at the output of UDF 2 for / Ni. Thus, a total of n predetermined frequencies can be formed.

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When the code is changed at the input of the RNG 8, a new one, randomly selected from n I values, is set, which determines the new value of the signal frequency at the UDCH 2 output.

With the arrival of UDF 2 ns pulses, the input of counter 3, it gradually fills up, and the number at its output tires increases from 0 to Ketch 1. Such cycles periodically repeat QHF times with a frequency of for / Ni-Ksch.

The first transducer 4 of the code is programmed so that with a consecutive increase in the number on its input (address) buses, the numbers on its outputs change according to a certain, for example, sinusoidal law.

With the DAC 5, the digital signal is converted to analog, and the filter b eliminates the constant component and smoothes the stepwise nature of the voltage.

As a result, at the output of the device, a random signal is formed, which is a segment containing the QDH periods of sinusoidal oscillations, each one without a phase interruption. The oscillation frequency inside the segment is fi for / Ni.Kc4 and randomly varies from segment to segment, taking one of n predetermined values. The coefficient Kdr can be made a multiple of not the whole period, but half of the oscillation period, by connecting

the input of the divider 7 frequency is not the older, but to the previous discharge of the counter 3. In this case, when Kdh 1, the frequency measurement takes place on the interval of each half-period, This process simulates low-frequency noises well.

The shaper of random signals allows generating output oscillations of any shape, as well as changing the structure of random signals quickly.

FORUMAWLAH AND ISLANDS

A random signal shaper containing a reference oscillator, a serially connected counter, a first code converter, a digital-to-analog converter and a low-pass filter, a second code converter, and a frequency divider from / and the fact that, in order to obtain the out-of-band spectrum components, we introduced a random generator numbers and controlled frequency divider, which is connected between the output of the reference oscillator and the input of the counter, while the input of the frequency divider is connected to the output of the counter, the output of the frequency divider connected to the input of a random number generator, the output of which is connected to the input of the second converter of the code, the output of which is connected to the control input of the controlled divisor.

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Claims (1)

Claim A random signal generator comprising a reference oscillator connected in series with a counter. a first code converter, a digital-to-analog converter and a low-pass filter, a second code converter and a frequency divider, characterized in that, in order to reduce the level of out-of-band components of the spectrum, a random number generator and a controlled frequency divider are introduced, which is connected between the output of the reference generator and the counter input, wherein the input of the frequency divider is connected to the output of the counter, the output of the frequency divider is connected to the input of the random number generator, the output of which is connected to the input of the second 30 converter code whose output is connected to the control input of a controlled frequency divider.