JPH0531740Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to an information reproducing apparatus such as a rotary head type digital audio tape recorder, and more particularly to an information reproducing apparatus having a high-speed search function.

BACKGROUND ART As a digital audio device, a playback-only disk player called a so-called compact disk that plays back small-diameter disks is known, but recently, digital audio devices that have both recording and playback functions are known. Tape recorders are being commercialized.

In a rotary head type DAT, which is one type of digital audio tape recorder (hereinafter abbreviated as DAT), subcode data is recorded on a magnetic tape along with PCM audio data. This subcode data includes, for example, identification information such as a start ID (S-ID) for cueing recorded at the beginning of each program information, and a unique program number corresponding to each program information. There is. Therefore, magnetic tape can be used at high speeds (e.g.
The recorded information is read while running at a speed (200 times faster than normal recording/playback), and the desired program information is quickly searched based on the identification information obtained from the read signal, the reproduced RF signal. Is possible.

That is, as shown in FIG. 2a, a program number unique to each program information is recorded at the beginning of each program information, and similarly, logic "1" information is recorded as start ID information. Alternatively, during playback, the reading of the program number is valid only during the period when the start ID information is detected, and the desired program information is detected based on the read program number, or the program number is displayed on the display section. It can be done.

Incidentally, in a rotary head type DAT, there may be an unrecorded portion of the RF signal between a plurality of pieces of program information (so-called between songs) recorded on the magnetic tape. Here, the magnetic tape with RF unrecorded areas between tracks is rotated in the reverse direction, that is, REV (Reverse).
Considering the case of searching in the direction, as shown in Figure 2a, for example, the fall of the start ID in the part where the program number is "7" is a part where the RF signal suddenly disappears, indicating the existence of the start ID. Since this is not known, the falling edge cannot be detected. In this case, the control unit considers that the start IDs are continuous in the RF unrecorded section, and
Since the reading of the program number is valid during the detection period of the start ID, as shown in FIG. 2b, the program number is regarded as "7" until just before the program number enters the program information section of "6". This causes problems in displaying program numbers and searching by program number.

Summary of the invention This invention was created in view of the points mentioned above.
An object of the present invention is to provide an information reproducing device that enables accurate reading of subcode information by preventing erroneous detection of subcode information in an RF unrecorded area.

The information reproducing apparatus according to the present invention includes an RF detection means for detecting that an RF signal is included in a read signal from a magnetic tape, an identification information detection means for detecting identification information from the read signal, and an RF detection means. and control means for performing various controls based on each detection output of the identification information detection means, and is configured to disable the detection output of the identification information detection means when no detection output is supplied from the RF detection means. .

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing one embodiment of a rotary head type DAT which is an information reproducing apparatus according to the present invention. In the figure, reference numeral 1 denotes a deck mechanism, in which a cassette 3 containing a magnetic tape 2 is stored.
is installed. The magnetic tape 2 is pulled out from the cassette 3, and a pair of rotating magnetic heads 4a, 4b
It is wound 90 degrees around a rotating drum 5 having a diameter. When the magnetic tape 2 is running at a normal recording/reproducing speed or at a medium speed several ten times that speed, the magnetic tape 2 is driven by a capstan 6 and a pinch roller 7 as tape driving means. When traveling at twice the high speed, the tape is driven by the supply reel motor 8 or the take-up reel motor 9 as tape driving means.

Signals read from the magnetic tape 2 by the pair of rotating magnetic heads 4a and 4b are taken out to the outside via a rotating transformer (not shown) and supplied to the reproduction amplifier 10. The read (reproduced) signal amplified by the reproducing amplifier 10 is extracted as a digital signal by the signal detection circuit 11 and then supplied to the signal processing circuit 12 and directly to the RF detection circuit 13 . The RF detection circuit 13 has, for example, an envelope detection circuit configuration, and detects that an RF signal is included in the reproduced signal,
A high level detection signal is output during the detection period. This detection signal is supplied to a control circuit 14, which will be described later. The subcode detection circuit 15 is the signal detection circuit 11
Detects subcode information (identification information) such as start ID and program number from the output data.
The detected subcode information is supplied to the control circuit 14. The signal processing circuit 12 performs processes such as decoding, error correction, and deinterleaving of read data. The read data subjected to these processes is converted into analog data by a D/A converter 16 and output as an original audio signal.

The control circuit 14 is composed of a microcomputer, etc., and operates the deck mechanism section in response to commands such as recording (REC), playback (PLAY), high-speed fast forward (FF), and high-speed rewinding (REW) from the input section 17. 1, and in the playback or search state, the start ID, program number, etc. detected by the subcode detection circuit 15 only during the period when the detection signal is generated from the RF detection circuit 13, that is, during the recording period of the RF signal. The subcode information is read and control such as cueing of the program information is performed.

Next, the procedure of the subcode information reading operation executed by the processor of the control circuit 14 will be explained with reference to the flowchart of FIG.

When a playback (PLAY) or search command is issued from the input unit 17 (step S1) and the magnetic tape 2 starts running, it is determined whether or not there is an RF signal by sensing the detection signal of the RF detection circuit 13. (step S2), and if yes, it is determined whether or not the start ID signal as a cue signal has risen by sensing the output of the subcode detection circuit 15 (step S3). ). Then, when the rising edge of the start ID signal is detected, reading of the program number starts (step
S4). Next, by sensing the output of the subcode detection circuit 15, it is determined whether or not the start ID signal has fallen (step S5), and at the moment when the falling of the start ID signal is detected, the start ID and program number are determined. Clear (step S6). Step S5
If the falling edge of the start ID signal is not detected in step S7, it is determined whether the RF signal has fallen (step S7), and if the falling edge has not been detected, the process returns to step S5 and the falling edge is detected. If it is, the process moves to step S6. Through the above series of operations, the program number as subcode information is read.

In this way, if the falling edge of the start ID signal is not detected, then by detecting the falling edge of the RF signal and clearing the program number information at the time of detection, for example, if RF is not recorded between songs, When searching in the reverse direction for a magnetic tape containing a program number, for example, if the program number is 7, the start
Even if the falling edge of the ID cannot be detected, it can be determined that the start ID signal has fallen at the falling edge of the RF signal. Program number "7" until just before entering the program information section of "
This will prevent things that could be seen as such.

In the above embodiment, when the detection signal is not supplied from the RF detection circuit 13, the subcode detection circuit 15 does not receive subcode information.
Although the case has been described in which the detection output of the subcode detection circuit 15 is disabled, it is also possible to stop the detection operation of the subcode detection circuit 15 when no detection signal is supplied from the RF detection circuit 13, and the same effect can be obtained. It will be done.

In addition, not only during a backward search but in all cases, when an RF signal is not detected, the detection output of the subcode detection circuit 15 is invalidated, thereby improving the reliability of the output information of the subcode detection circuit 15.

Effects of the Invention As explained above, according to the present invention, the detection operation of the subcode detection circuit is disabled when no RF signal is detected. Even if it is not possible to detect the falling edge of the cueing signal due to the Can read numbers accurately.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is an explanatory diagram of the operation at the time of backward search, and FIG. 3 is a flowchart showing the procedure of the subcode information reading operation executed by the processor. Explanation of symbols of main parts, 1... Deck mechanism part,
2... Magnetic tape, 4a, 4b... Rotating magnetic head, 5... Rotating drum, 6... Capstan, 8
... Supply reel motor, 9 ... Take-up reel motor, 12 ... Signal processing circuit, 13 ... RF detection circuit, 14 ... Control circuit, 15 ... Subcode detection circuit.

Claims (1)

[Scope of utility model registration request] A magnetic tape playback device in which a plurality of program information and various types of identification information are recorded at the beginning of each program information, and a radio frequency (RF) signal is included in the read signal from the magnetic tape. an RF detection means for detecting the identification information; an identification information detection means for detecting the identification information from the read signal; and a control means for performing various controls based on detection outputs of the RF detection means and the identification information detection means. An information reproducing apparatus, characterized in that the control means controls to invalidate the detection output of the identification information detection means when the detection output is not supplied from the RF detection means.