A recording and reproducing system is disclosed in U.S. Pat. No. 4,680,647 which enables voice to be added to pictures obtained at the time of still picture reproduction of recorded information in a recording medium, by executing recording in a recording medium, for example, inserting a digital data including voice information after compressing the time base in a portion of a video format signal and by inserting video information in the remaining portion.
The prior art reproducing processor for reproducing and processing a video format signal recorded in a recording medium with such a system is shown in FIG. 1. In FIG. 1, a disk 1 serving as a recording medium is driven to be rotated by a spindle motor 2. As the disk 1 is rotated, a signal recorded in the disk 1 is read by a pickup 3. The pickup 3 is carried by a slider (not shown) which is moved in the radial direction of the disk 1, and the information detection point (light spot for information detection) of the pickup 3 can freely be positioned in the radial direction of the disk 1. Further, various servo systems such as a spindle servo system, tangential servo system and tracking servo system are also provided. However, they are already well known so that they will not be shown here.
The so-called RF (high frequency) signal output from the pickup 3 is supplied to a video demodulation circuit 6 after it is amplified by an RF amplifier 5. The video signal is demodulated in the video demodulation circuit 6 by undergoing the frequency demodulation processing of the RF signal. The demodulated video signal is supplied to a dropout correction circuit 7. To the dropout correction circuit 7 there is supplied, for example, a high level dropout detection signal from a dropout detection circuit 8. The dropout detection circuit 8 has a constitution in which a dropout detection signal is generated, for example, when the interval between the zero cross points of the RF signal exceeds a predetermined value. Further, the dropout correction circuit 7 is so constructed as to correct the dropout upon receipt of a dropout detection signal, by outputting the dropout section of the video signal by replacing it with the video signal at the time by 1H earlier from now. The output of the dropout correction circuit 7 is supplied to a time base error correction circuit 9. The time base error correction circuit 9 has a variable delay element of, for example, CCD, and is constructed so as to eliminate litters due to eccentricity of the disk or the like by delaying the output of the dropout correction circuit 7 by a time corresponding to the phase difference between the reference signal with a predetermined frequency and the horizontal synchronizing signal in the output of the dropout correction circuit 7.
A video format signal whose jitters are removed by the time base error correction circuit 9 is supplied to a pulse waveform shaping circuit 10. The pulse waveform shaping circuit 10 consists, for example, of an equalizer having predetermined amplitude and phase characteristics. A video format signal which underwent pulse waveform shaping by which its amplitude is corrected and phase is compensated for by the pulse waveform shaping circuit 10 is supplied to a hue correction circuit 11 and a signal separation circuit 12. The hue correction circuit 11 has, for example, a variable delay element analogous to the time base error correction circuit 9, and it is constructed so as to eliminate jitters in chroma level by delaying the video format signal by a time corresponding to the phase difference between the color burst in the video format signal and a reference signal with a predetermined frequency. The output of the hue correction circuit 11 is supplied to a noise reduction circuit 13 with a constitution by which, for example, a micro level of the signal is detected and added to the original signal with reversed phase. After suppression of noise with this arrangement, the signal is supplied to a character insertion circuit 14. The character insertion circuit 14 has a constitution by which a video signal corresponding to the character indicated by the data sent from a system controller 15 is synthesized with the video format signal output from the noise reduction circuit 13. The output of the character insertion circuit 14 is supplied to the output terminal OUT.
On the other hand, in the signal separation circuit 12, horizontal and vertical synchronizing signals and a control signal indicating the recording position inserted to the portion corresponding to a predetermined line in the flyback period are separated out from the video format signal and are supplied to the system controller 15. The system controller 15 is composed of a microcomputer consisting, for example, of a processor, ROM, RAM and the like, and carries out arithmetic operation based on a data or program stored in ROM, RAM or the like by a command supplied from an external equipment. The system controller 15 then supplies instruction signals such as play, pause, search and the like to a playing unit control circuit 16 and supplies a data designating a character to be inserted to the character insertion circuit 14.
With the constitution as in the above, when a dropout is generated in a section where a digital data of a video format signal is inserted, the section is replaced by the signal precedent by 1H, creating an inconvenience that an uncorrectable error is generated in the digital data. Moreover, the amplitude characteristic and the phase characteristic of the digital data are set by the digital data waveform shaping circuit 9 so as to give a minimum read error rate. For this reason, there has also been a drawback in that the variable ranges in video making such as the adjustment of the amount of noise reduction and frequency characteristic for the section carrying the video information of the video format signal becomes narrowed down making it different to obtain a desired video.