JPH0535460Y2 - - Google Patents

Description

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

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 (hereinafter abbreviated as DAT) are becoming commercialized.

In a rotary head DAT, which is one type of DAT, subcode data is recorded on a magnetic tape along with PCM audio data. This subcode data includes, for example, the start code for cueing recorded at the beginning of each program information.
It includes identification information such as an ID (S-ID) and a unique program number (identification number) corresponding to each program information. Therefore, the recorded information is read while running the magnetic tape at high speed (for example, 200 times the speed of normal recording/playback), and the desired information is determined based on the identification information obtained from the reproduced RF signal that is the read signal. Quickly search program information
It is possible to do so.

One method of this high-speed search is, for example, by comparing the program number at the current position detected from the reproduced RF signal and the program number at the specified search destination, and detecting a match between the two program numbers. A commonly considered method is to search for desired program information. In such a search method, in order to detect program number information, which is subcode data, it is necessary to separate and extract the clock from the reproduced RF signal. Therefore, the clock separated and extracted from the reproduced RF signal is used as a predetermined reference signal so that the relative speed between the rotating magnetic head and the magnetic tape during high-speed search is approximately the same as during normal recording and reproduction. Compare the phase,
A so-called drum servo is applied to control the rotation of a rotating drum (rotating magnetic head) according to the error signal.

By the way, in a rotary head type DAT, as shown in FIG. 2, there may be unrecorded portions of RF signals between a plurality of pieces of program information (so-called gaps between songs) recorded on a magnetic tape. When performing a high-speed search on a magnetic tape in which there are unrecorded RF signals between songs, the clock needed for the drum servo cannot be extracted because the reproduced RF signal cannot be obtained between the songs, and the drum servo cannot be locked. It may come off. In this state, even if the RF signal recording section (next program information) is entered again, it takes time for the drum servo to lock again, so the subcode data recorded immediately after the song interval may be missed. Sometimes. As a result, desired program information cannot be accurately searched.

Summary of the invention This invention was created in view of the points mentioned above.
It is an object of the present invention to provide a high-speed information retrieval device that can quickly and reliably perform a search operation based on a program number even on a magnetic tape in which an unrecorded portion of an RF signal exists.

The high-speed information retrieval device according to the present invention, when detecting an RF unrecorded portion during a high-speed search operation, detects the RF unrecorded portion only when it detects program information that is one point earlier than the specified program information in the tape running direction. The vehicle is configured to start traveling at a low speed from the beginning, and to search for designated program information by reading the program number information from the read signal during the low speed traveling.

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

FIG. 1 is a block diagram showing an embodiment of a rotary head type DAT to which a high-speed information retrieval device according to the present invention is applied. In the figure, reference numeral 1 denotes a deck mechanism section, and a cassette 3 containing a magnetic tape 2 is attached to the mechanism section. The magnetic tape 2 is pulled out from the cassette 3 and wound 90 degrees around a rotating drum 5 having a pair of rotating magnetic heads 4a and 4b. The magnetic tape 2 is used for normal recording and recording.
When traveling at the reproduction speed or at a medium speed several ten times that speed, the vehicle is driven by the capstan 6 and the pinch roller 7. For example, when traveling at a high speed of 200 times, the supply reel motor 8 or the take-up reel is used. It is driven by a motor 9. The starting and ending ends of the magnetic tape 2 are detected by detection circuits 10 and 11.

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 12. The read (reproduction) signal amplified by the reproduction amplifier 12 is extracted as a digital signal by the signal detection circuit 13 and then supplied to the signal processing circuit 14 and also directly supplied to the RF detection circuit 16 . The signal processing circuit 14 performs processes such as decoding, error correction, and deinterleaving of read data. After these processes are performed, the read data is converted into analog data by the D/A converter 15 and output as the original audio signal.

The RF detection circuit 16 has, for example, an envelope detection circuit configuration, detects whether an RF signal is included in the reproduced signal, and generates a detection output when detecting that the RF signal is not included.
This detection output is supplied to a control circuit 22, which will be described later. The program number detection circuit 17 detects program number (identification number) information from the output data of the signal detection circuit 13. This detected program number (currently abbreviated as PNo) information is held in the holding circuit 18 until, for example, the next program number information is detected, and if it matches the program information held in advance in the holding circuit 19, It is detected by the coincidence detection circuit 20. The holding circuit 19 includes an operating section 2
1, for example, program number (hereinafter abbreviated as target PNo) information of desired program information specified by key input and program number information one point earlier than the target PNo in the tape running direction, that is, FWD (Forward). (Target PNo-1) information is held in the direction, and (Target PNo+1) information is held in the REV (Reverse) direction.
The coincidence detection circuit 20 detects that the current PNo information (target PNo)
-1) Output a first detection signal when matching the information or (target PNo+1) information, and output a second detection signal when matching the target PNo information. These detection signals are supplied to the control circuit 22.

The control circuit 22 is composed of a microcomputer, etc., and is configured to drive the magnetic tape 2 in the FWD direction (forward direction) or the REV direction (reverse direction) at high speed in response to a high-speed search command from the operation unit 21. The deck mechanism section 1 is driven and controlled, and a detection output is generated from the RF detection circuit 16 in this high-speed running state.
Moreover, if the first detection signal is being supplied from the coincidence detection circuit 20, the deck mechanism unit 1
Further, in this low-speed running state, in response to a second detection signal supplied from the coincidence detection circuit 20, the deck mechanism 1 is driven and controlled to run the magnetic tape 2 at a constant speed.

Note that in the configuration described above, the holding circuit 1
Although the holding circuits 18, 19 and the coincidence detection circuit 20 have been described as hardware separate from the control circuit 22, the holding circuits 18, 19 and the coincidence detection circuit 20 are different from the control circuit 22.
2 and a microcomputer, and the high-speed search operation can be executed according to a predetermined program. Hereinafter, the procedure will be explained along the flowchart of FIG. 3.

The processor inputs the target PNo in the operation unit 21.
is specified and a high-speed search command is issued (step S1), first, the specified target PNo and current PNo are compared (step S2), and if target PNo > current PNo, a high-speed search in the FWD direction is performed. A command is issued to the deck mechanism 1 to start (step S3). During this high-speed search in the FWD direction, when a falling edge of the RF signal is detected by sensing the output of the RF detection circuit 16 (step S4), the current PNo and target PNo-1 are compared (step S5). , if they match, then the rising edge of the RF signal is detected (step S6), and at the rising edge of the RF signal, a command is issued to the deck mechanism 1 to run the magnetic tape 2 in the REV direction at medium speed (step S6). S7). Then, when it is detected that the RF signal has fallen again (step S8), a command is issued to the deck mechanism 1 to shift to a low-speed running state in the FWD direction at this point (step S9). Here, low-speed running refers to a running state in the process of gradually rising toward high-speed running, or a running state at a certain constant speed.

In this low-speed running state, the current PNo and the target PNo are compared (step S10), and if it is determined that they match, the deck mechanism 1 is driven and controlled to perform a precise cueing operation (step S11), and then the deck mechanism 1 is driven at high speed in the FWD direction. End search. If it is determined in step S10 that there is no discrepancy, it is determined whether or not it is the end of the tape by sensing the output of the tape end detection circuit 11 (step S12), and if it is the end of the tape, the FWD is activated.
The high-speed direction search is completed, and if the tape is not at the end, the process returns to step S4. FIG. 2a shows a timing chart of a high-speed search operation in the FWD direction when searching for program number "5", for example. Furthermore, in step S2, the target PNo.
= If it is determined that the current status is PNo, the process directly proceeds to step S11.

On the other hand, in step S2, target PNo<current
If it is determined to be PNo, a command is issued to the deck mechanism 1 to start a high-speed search in the REV direction (step S13). During this high-speed search in the REV direction, when a falling edge of the RF signal is detected (step S14), the current PNo and target PNo+1 are compared (step S15), and if they match, the rising edge of the RF signal is subsequently detected. (Step S16) At the rise of this RF signal, a command is issued to the deck mechanism 1 to run the magnetic tape 2 in the FWD direction at a medium speed (Step S17). Then, when it is detected that the RF signal has fallen again (step S18),
At this point, a command is issued to the deck mechanism 1 to shift to a low-speed running state in the REV direction (step S19). In this low-speed running state, the current PNo and the target PNo are compared (step S20), and if they match, the high-speed search in the REV direction is completed via step S11. If it is determined in step S20 that there is no match, it is determined whether or not it is the beginning of the tape by sensing the output of the tape beginning detection circuit 10 (step S22), and if it is the beginning of the tape, the high-speed search in the REV direction is terminated. However, if it is not the beginning of the tape, the step
Return to S14. FIG. 2b shows a timing chart of a high-speed search operation in the REV direction when searching for program number "4", for example.

In this way, when an RF unrecorded area is detected during a high-speed search operation, only when a PNo that is one position before the target PNo in the tape running direction is detected.
By shifting to low-speed running from the RF unrecorded area, when the magnetic tape 2 enters the RF signal (program information) recording area again, the magnetic tape 2 is running at low speed, and the drum servo is unlocked in the RF unrecorded area. is relocked within the subcode area, so
This means that the program number necessary for the search recorded at the RF signal recording start point can be reliably read.

In the above embodiment, the control circuit 22 performs the transition from the RF unrecorded area to low-speed running using software. (not shown) is inserted, and this time constant circuit is activated when transitioning from the RF unrecorded area to low-speed running to drive the reel motors 8 and 9.
It is also possible to construct a structure in which the drive voltage applied to the drive voltage is gradually raised to cause the drive voltage to rush into the RF recording section while running at a low speed.

In addition, in the above embodiment, when the rising edge of the RF signal is detected during the high-speed search in the FWD direction, the vehicle is caused to travel in the reverse direction at a medium speed, and after the RF signal falls, the vehicle is driven at a low speed. It is also possible to read the program number information while traveling in the direction, compare the current PNo and the target PNo, and if they do not match, then start a high-speed search in the FWD direction.

Effects of the invention As explained above, according to the invention, when an RF unrecorded area is detected during a high-speed search operation,
1 point before the target P No. in the tape running direction.
Only when PNo is detected, the RF non-recorded area is moved to low-speed running, and the drum servo that is unlocked in the RF signal-unrecorded area is sub-activated. Since it can be relocked within the code area, the program number information recorded at the RF signal recording start point can be read quickly and reliably, resulting in perfect high-speed search operations based on the program number.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is a timing chart during a high-speed search executed by the circuit of FIG. 1, and FIG. 3 is a flowchart showing the procedure of a high-speed search executed by a 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, 14 ... Signal processing circuit, 16 ... RF detection circuit, 17 ... Program number detection circuit, 20 ...
Coincidence detection circuit, 22...control circuit.

Claims (1)

[Scope of utility model registration request] A high-speed information retrieval device for a magnetic tape reproducing device in which identification number information unique to the program information is recorded at the beginning of each program information together with a plurality of program information, the tape running on the magnetic tape. a driving means; a control means for driving and controlling the tape driving means; a specifying means for specifying desired program information; and detecting when a radio frequency (RF) signal is not included in a read signal from the magnetic tape. RF detection means for generating an output;
identification number detection means for detecting the identification number information from the read signal; and program information that is one point earlier than the specified program information in the tape running direction based on the identification number information detected by the identification number detection means. program information detection means for detecting program information; the control means causes the magnetic tape to travel at high speed in response to a high-speed search command, and when a detection output is generated from the RF detection means during this high-speed travel; Information characterized in that, only when detected by the program information detection means, the tape drive means is driven and controlled so as to start running the magnetic tape at a low speed from the interval in which the detection output of the RF detection means is generated. High speed search device.