SU506058A1 - A device for recording and analyzing signals - Google Patents

Description

one

The invention relates to a magnetic recording technique, in particular, to recording and analyzing devices with adjustable carrier speed. It can be used in the analysis of vibration signals of a gas turbine engine in acceleration mode.

A device for recording and analyzing signals with a time scale correction of a reproduced signal, comprising a tape mechanism, a recording unit and an adder connected to it, one input of which is connected to a signal source, a playback unit whose output is connected to a meter, a reference signal sensor, is known. , filters and discriminator, the output of which is connected to the block correction time scale.

The known device does not allow changing the time scale of the signal under study, which makes it difficult to analyze the spectrum of such signals as, for example, the vibration signal of a gas turbine engine in the acceleration mode.

In the proposed device, this disadvantage is eliminated due to the introduction of two mixers with heterodyne, the first mixer is connected to the sensor signal of the reference frequency and through the filter to the second input of the adder, and the second mixer is connected to the playback unit and another filter.

The drawing shows a block diagram of the proposed device.

The device contains a tape mechanism 1, a recording unit 2 with a recording head 3 connected to it, a playback unit 4 with a playback head 5 connected to it, a vibration signal source 6 mounted on a gas turbine engine (not shown), and a signal sensor 7 reference frequency, adder 8, first mixer 9, first local oscillator 10, filter

11 intermediate frequency, second mixer 12, second local oscillator 13, reference frequency filter 14, discriminator 15, 6vioK 16 time scale correction, connected to the driving motor 17 of the tape mechanism 1, which also includes pressure roller 18 and coil 19 with magnetic carrier 20. A meter 21, for which, for example, a spectrum analyzer can be used, is connected to the top of the playback unit 4.

The device works as follows. In the recording mode, the signal from the reference frequency sensor 7 is fed to the first mixer 9, in which the frequency of the main signal is transferred by the signal of the first local oscillator 10 to the B frequency range, which lies above the frequencies of the spectral components of the vibration signal. The signal from the output of the mixer 9 is fed to the input of the filter 11, the output of which is allocated an intermediate frequency. The intermediate frequency signal is mixed in the adder 8 with the signal source 6 vibrations. The total signal by the amplifier in block 2 and the recording head 3 is recorded on the same track of the carrier 20. Recording two signals on the same track of the carrier eliminates the inter-channel distortion inherent in multi-track recording.

In the "playback" mode, the signal from the head 5, amplified in block 4, is fed to the input of the second mixer 12 and simultaneously to the meter 21. The second local oscillator 13 converts the intermediate frequency into a signal that is extracted by the filter 14 and acts on the discriminator 15, ensuring the formation of a command signal . Under the action of this signal, the time scale correction unit 16 and the leading motor 17 change the speed of the carrier 20 so as to keep the parameters of the signal acting on the discriminator 15 constant. By varying the frequencies of the local oscillators 10 and 13, the frequency ratio of the sensor signal 7 and the reference signal is changed by the output of the filter 14, i.e., change the ratio of the reproduction speeds and the frequency of the sensor 7 (the frequency of the sensor is proportional to the speed of the gas turbine engine and the frequency of vibrations).

The change in the playback speed relative to the frequency of the vibrations to a change in the time scale of the process under study, at the same time, the drift of the spectrum of the vibration signal as a result of acceleration is compensated for by obtaining the error signal when the frequency of the reference signal at the output of the filter 14 changes.

Claims (1)

Invention Formula A device for recording and analyzing signals, containing a tape mechanism, a recording unit and an adder connected to it, one input of which is connected to a signal source, a playback unit whose output is connected to a meter, a reference frequency signal sensor, filters and a discriminator, an output which is connected to a time scale correction block, characterized in that, in order to change the time scale of the process under study, two mixers with heterodyne are introduced into it, the first the mixer is connected to the signal sensor of the reference frequency and through a filter to the second input of the adder, and the second mixer is connected to the playback unit and another filter.