SU788154A1 - Device for reproducing frequency-modulated signals - Google Patents

Description

one

The invention relates to instrumentation, in particular to magnetic recording apparatus using a frequency modulated recording method.

Devices are known for reproducing a frequency-modulated signal with error compensation due to instability of carrier speed, using the principle of subtracting, dividing or multiplying information and reference signals 1.

However, these devices do not allow the range of error compensation to be expanded to the required degree.

The closest in technical essence to the present invention is a device for reproducing frequency-modulated signals, comprising information and reference signal shapers, a frequency modulator and a pulse shaper filled, the output of which is connected to the first input of converter 2.

However, this device does not eliminate the reproduction error, which is generated due to the loss of pulses as information. So is the reference signal.

In addition, the intermediate conversion of the reference signal, i.e., frequency demodulation-modulation, introduces an additional error.

The purpose of the invention is to improve reproduction accuracy.

The goal is achieved. We note that a frequency multiplier with phase-locked loop connected between the output of the information signal shaper and the second is entered into a device for reproducing frequency-modulated signals containing information and reference drivers. the converter input, and the filling pulse driver, associated with the output of the reference signal driver, is also made in the form of a multiplier Phase-locked stati.

Claims (2)

20 In FIG. 1 is a block diagram of a magnetic media playback device; in fig. 2 - the characteristic of the clever frequency inhabitant; in fig. 3 is a frequency multiplier circuit diagram with phase auto tuning; in fig. 4 - the characteristic of the operational amplifier multiplier. The circuit contains information signal shaper 1, which is connected via phase multiplier 2 to phase converter 3, to a code whose other input is connected to reference signal shaper 4 via shaper frequency generator shaper 5, which is also a phase locked loop. The frequency multiplier (Fig. 3) contains a phase comparator 6 made on a trigger with a separate start, a low-frequency filter 7 (LPF), a non-linear operational amplifier 8, a controlled oscillator 9, and a frequency divider 10. The device works as follows. The signal from the phase comparator, formed by the phase shift between the input frequency and the divided frequency divider, the output frequencies, is extracted by a low-frequency filter, amplified by a non-linear operational amplifier and controls the generator. Since the non-linear operational amplifier has the characteristic shown in FIG. 4, the range of operation of the controlled generator is characterized by the graph shown in FIG. 2. Indeed, if there is no signal at the input of the frequency multiplier, then the output will be the frequency / s (Fig-2), which corresponds to the minimum frequency of the frequency-modulated information signal. If the characteristic of the operational amplifier included in the frequency multiplier were linear, then the U-generator would fail due to the output of the frequency multiplier from the capture band, i.e. the output of the frequency multiplier would be zero. In case of presence of interference, the operation of the device is similar with the only difference that the output of the frequency multiplier is a signal with a frequency UAXC. Thus, the use of a nonlinear operational amplifier in the frequency multiplier allows to obtain, in any case, the AHp that reduces the error. In addition, the frequency multiplier reduces the error in the case of short-term interference and disturbances most characteristic of magnetic registers. This is explained by the fact that when this data is lost, the integrating effect of the low-pass filter is affected. The cut-off frequency of the filter is selected on the one hand from the condition of passing the required width of the information signal spectator, on the other hand, to ensure the operation of the frequency multiplier, the following condition must be fulfilled: one or several informational impulses, which corresponds to a short-term failure, or if there are one or several false impulses at the input of the multiplier, the frequency of creatures at its output It does not change due to the inertia of the filter. The converter 3 is made according to the principle of filling the frequency signal with the frequency multiplied by the intervals generated from the multiplied information signal. The use and use of a frequency multiplier with phase auto-tuning in the channel of the information signal and as a frequency-shaper reduces the error due to the presence of,. em interference and loss of pulses. In addition, multiplying the frequency of the signals at the output of the frequency converter into the code increases the speed of the device. Apparatus of the Invention A device for reproducing frequency-modulated signals, comprising information and reference signal drivers and a shaper pulse generator, the output of which is connected to the first input of the converter, characterized in that, in order to increase the reproduction accuracy, a phase self-tuned frequency multiplier connected between the output of the information signal shaper and the second input of the converter, and the shaper of the filling pulses associated with the output of the forms The reference signaling device is also provided in the form of a frequency multiplier with phase-locked loop. Sources of information taken into account during the examination 1. Author's certificate of the USSR No. 458858, cl. G 11 B 5/02, 02.27.72. 2. USSR author's certificate number 459798, cl. G П В 5/00, 10.03.72 (about the type). may . Jml min