JPH0616343B2 - Distortion removal playback device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distortion elimination reproducing apparatus, for example, a reproducing apparatus for a medium such as a VTR or a video disc player which records a frequency-modulated signal.

[Conventional technology]

 The structure of a conventional device of this type is shown in FIG.

In this figure, (1) is a reproducing mechanism, which reproduces the signal from a recording medium (not shown) in which an appropriate signal is frequency-modulated and recorded. (2) is connected to the above-mentioned reproducing mechanism, detects a temporal variation of the traveling system and the rotational system such as a variation of the image signal thereof, a variation of the rotation number of the motor, and outputs a signal according to the detection result. Jitter error detector,
(3) is a control circuit for controlling the reproducing apparatus by receiving the output of the detector, which controls so as to reduce the above-mentioned temporal fluctuation. (4) is a demodulator which reproduces and outputs the FM signal taken out from the recording medium by the reproducing apparatus as a recorded signal, and (5) is its output terminal.

Fig. 4 shows the waveform when a non-modulated signal is reproduced by the above reproducing device. (A) is the output waveform of the jitter error detector (2), (B) is the output waveform of the demodulator (4). Is.

[Problems to be solved by the invention]

The conventional device is configured as described above, and is shown in FIG. 4 (A).
The output of the jitter error detector (2) shown in Fig. 4 directly modulates the FM signal taken out from the reproducing mechanism (1), and the output of the demodulator (4) shows the distortion component as shown in Fig. 4 (B). Therefore, it is necessary to make the jitter error amount as small as possible, so that it is necessary to increase the accuracy of the reproducing mechanism and increase the amplification degree of the control circuit to enhance the control capability. In addition, there was a problem that the distortion component could not be reduced to zero even with this method.

The present invention has been made in order to solve such a problem, and it is possible to reduce the control capability of the reproducing mechanism to such an extent that there is no problem in the reproducing function, and it is possible to reduce the time required for the reproducing mechanism in reproducing output. It is an object of the present invention to provide a device capable of eliminating the influence of fluctuation.

[Means for solving problems]

The reproducing apparatus according to the present invention is provided with a demodulator for demodulating a signal from the reproducing mechanism and an amplitude adjuster for adjusting the amplitude of the signal corresponding to the temporal change of the reproducing mechanism. The output of the regulator is differentially coupled.

[Action]

Since the output of the demodulator and the output of the amplitude adjuster are differentially coupled, it is possible to remove only the distortion component from the demodulated reproduction output, and thus reduce the control capability of the reproduction mechanism. Is possible.

Example of Invention

An embodiment of the present invention shown in FIG. 1 will be described below.

In this figure, (6) is a bandpass filter that removes unnecessary frequency components from the output of the jitter error detector,
(7) is an amplitude adjuster that adjusts the amount of jitter error by adjusting the amplitude of the output of the bandpass filter, and (8) is a mixer that differentially couples the output of the amplitude adjuster and the output of the demodulator. A mixer (9) is an output terminal of the mixer, and is for extracting the reproduction output from the demodulator.

The other structure is similar to that of the conventional device shown in FIG. Incidentally, FIG. 2 shows a waveform when a non-modulated signal is reproduced by the above reproducing apparatus,
(A) shows the output waveform of the amplitude adjuster (7), (B) shows the output waveform of the demodulator (4), and (C) shows the output waveform of the mixer (8).

In such a configuration, in the reproducing mechanism (1), the jitter error detector (2) detects the temporal fluctuations of the traveling system and the rotating system during the reproducing operation as in the conventional device. Control circuit according to the signal corresponding to (3)
However, the playback mechanism (1) is controlled so as to reduce the temporal fluctuation.

The FM signal taken out from the recording medium (not shown) by the reproducing mechanism (1) is reproduced as a signal recorded by the demodulator (4). The distortion component as shown in () is included.

On the other hand, the output of the jitter error detector (2), which has detected the time variation of the reproduction mechanism (1), has the bandpass filter (6) to remove unnecessary frequency components, and the amplitude adjuster (7).
Thus, the amplitude is adjusted to the same amplitude as the distortion component included in the output of the demodulator (4) and the result is as shown in FIG. 2 (A). The output of the demodulator (4) containing distortion and the output of the amplitude adjuster (7), which is a distorted signal, are differentially given to the mixer (8), so that the demodulator in the mixer (8) The distortion component of the output of (4) is subtracted and the reproduction output is taken out to the output terminal (9). This circuit operates by a simple adjustment of reproducing the unmodulated signal and setting the amplitude adjuster (7) so that the reproduction output noise is minimized.

Although the above embodiment shows that there is no time delay between the demodulated distortion-containing signal and the output signal of the jitter error detector, if there is a time delay between them, demodulation is performed. The same effect can be expected if the time is adjusted by delaying either the generated distortion-containing signal or the output signal of the jitter error detector by a delay circuit. Further, in the case of an apparatus in which all signals are FM recorded, the control circuit (3) can be omitted, so that it can be manufactured at low cost.

〔The invention's effect〕

Since the present invention is configured as described above, it is possible to obtain a good quality reproduced signal without distortion without increasing the accuracy of the reproducing mechanism and accuracy.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing signal waveforms of respective parts at the time of reproducing an unmodulated signal in the above embodiment, and FIG. 3 is a schematic configuration diagram showing a conventional device. , FIG. 4 is a diagram showing signal waveforms of respective portions when reproducing a non-modulated signal in a conventional device. In the figure, (1) is the playback mechanism, (2) is the jitter error detector,
(3) is a control circuit, (4) is a demodulator, (5) is a reproduction output terminal, (6)
Is a bandpass filter, (7) is an amplitude adjuster, (8) is a mixer, and (9) is an output terminal of the mixer. The same reference numerals indicate corresponding parts.

Claims (2)

[Claims] 1. When reproducing a frequency-modulated and recorded signal, the reproducing mechanism is controlled so as to detect a temporal variation of a traveling system and a rotating system of the reproducing mechanism and correct the variation. , A demodulator for demodulating the signal from the reproducing mechanism and an amplitude adjuster for adjusting the amplitude of the signal corresponding to the fluctuation are provided, and the output of the demodulator and the output of the amplitude adjuster are differentially A distortion removing / reproducing apparatus characterized in that the distortion component based on the above fluctuation is removed by combining them. 2. A signal corresponding to a time variation of a reproducing function is
A jitter error detector for detecting a temporal change of a traveling system and a rotation system of a reproducing function, and a bandpass filter for removing an unnecessary frequency component contained in the output of the detector are taken out. The distortion removing / reproducing apparatus according to the first aspect.