JPS6223391B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a program search device capable of searching for a program to be searched while driving a recording medium on which a plurality of programs are recorded at high speed. In such a conventional device, when a plurality of programs are recorded on a recording medium, for example, a magnetic tape, and when searching for a program to be searched,
The magnetic tape is driven at one type of high speed to the program to be searched. The driving speed in this case is limited to about 10 to 30 times the driving speed when reproducing the magnetic tape. This speed limitation in high-speed drive of the magnetic tape during program search is achieved by preventing the playback magnetic head from digging into the first recorded part of the program to be searched due to the inertia of the magnetic tape drive mechanism. This is so that the magnetic tape can be stopped immediately before the beginning of a program, or the drive speed can be accurately switched and limited to the drive speed during playback. Therefore, if a large number of programs are recorded and the driving distance is long from the search position on the magnetic tape at the time of starting the search to the search position on the magnetic tape where the program to be searched is recorded, the There is a problem in that the search period from the time to the end of the search is naturally long (for example, several minutes). This invention was made in order to solve the above-mentioned problem, and the search period from the start of the search to the end of the search is sequentially divided into a first search period and a second search period. In the first search period, there is no need to consider the inertia of the drive mechanism for the recording medium, so the recording medium can be driven at the first type of high speed, which is higher than the normal fast forward or rewind drive speed. However, in the second search period, the above-mentioned inertia force is taken into account, and the recording medium is configured to be able to be switched and driven at a second type of high speed, thereby making it possible to significantly shorten the search period for the program to be searched. The purpose of the present invention is to provide a program search device that uses the following methods. In order to achieve the above-mentioned object, the present invention is capable of searching for a program to be searched in a recording medium while the recording medium is being driven at high speed. The period required from the start of the search to the end of the search is sequentially divided into a first search period and a second search period, and during the first search period, the recording medium is fast forwarded or rewinded at a speed higher than the first type. The recording medium is driven at a high speed and during the second search period, the recording medium is driven at a second type of high speed that is lower than the first type of high speed and faster than the playback speed. a first time constant corresponding to the first type of high speed for detecting a non-recorded portion in the recording medium during the first search period; and a first time constant for detecting the non-recorded portion in the recording medium during the second search period. and a second time constant corresponding to the second type of high speed. detecting the non-recorded portion in the recording medium based on the time constant, and generating a first detection signal every time the non-recorded portion is detected, and detecting the non-recorded portion in the recording medium according to the second time constant during the second search period. a signal generating means that generates a second detection signal when detected based on the signal generating means; and a signal generating means that generates a second detection signal when detected based on the signal generating means, and counting and skipping the number of the unrecorded portions up to the program to be searched based on the first detection signal from the signal generating means. a counting means for generating a speed switching signal when the number of programs to be processed becomes equal to or less than a predetermined value; and a signal generating means for switching the driving means from a first type high speed to a second type high speed based on the speed switching signal. switching means for switching the time constant of the above to a time constant corresponding to the second type of high speed, and the program position to be searched based on the second detection signal obtained from the signal generating means during the second search period. The present invention provides a program search device characterized in that a desired operating state is achieved in the following manner. Embodiments of the present invention will be described in detail below with reference to the drawings. Embodiments of the present invention relate to a program search device for a tape recorder in which the recording medium for a program to be searched is a magnetic tape, and the program is a track list of music, etc. The magnetic tape is driven at high speed up to that point, and when the track to be listened to is reached, the magnetic tape is automatically driven at the running speed of the playback state. That is, the drawing is a schematic illustration of the main parts of the apparatus according to the embodiment of the present invention, and to explain the drawing, T.
is a magnetic tape T, on which a plurality of programs are continuously recorded with fixed length unrecorded sections interposed between adjacent programs.
H is a magnetic head for playback only or for both recording and playback, and when recording or playing back a program on a magnetic tape, the magnetic head H contacts the magnetic tape T with a predetermined pressing force and also presses against the magnetic tape. When the above program is searched, it is configured to contact the magnetic tape T with a pressing force that is slightly less than the above-mentioned pressing force. Incidentally, when the magnetic tape T is driven in a normal fast forward or rewind state, the magnetic head H does not come into contact with the magnetic tape T. When searching for a program to be listened to on the magnetic tape T, this magnetic head H has a function of detecting unrecorded portions intervening between programs, and the detection output regarding the unrecorded portions is sent to the next stage detection circuit. Introduced into the input section of IC ₁ . The detection circuit _IC1 is also a waveform shaping circuit, and converts the distorted waveform output from the magnetic head H into a rectangular signal whose pulse width is controlled by a time constant circuit, which will be described later. Then, for example, a detection output is derived from the magnetic head H for a pause part (unrecorded part) of a song that is intervening in the program, and the detection output is introduced into the input section of the detection circuit IC ₁ . A time constant circuit A is connected to the detection circuit IC ₁ in order to distinguish the detection output from the magnetic head H regarding the non-recorded portion and the non-recorded portion intervening between the programs. That is, the time constant circuit A has a length such that the unrecorded portion continues for a predetermined length or more on the magnetic tape T even if a signal related to any of the above-mentioned unrecorded portions is applied to the input section of _the detection circuit IC1. If this is not the case, no signal relating to the unrecorded part will be derived to the output section, and therefore the unrecorded part intervening between programs will be replaced by the unrecorded part related to the above-mentioned pause part (anticipated during recording). If the time constant of time constant circuit A is set to correspond to the unrecorded part between the programs, The signal derived from the output part of the detection circuit IC ₁ corresponds to the unrecorded portion interposed between the programs. Note that this time constant can be changed in accordance with the driving speed of the magnetic tape, as will be described later. IC ₁ is an n-digit shift register, and the input section

Each time the output of the detection circuit IC ₁ is applied to [Equation], that is, each time an unrecorded portion between programs is detected, stored information is sequentially moved. Then, when n programs are recorded on the magnetic tape T and the magnetic head is located at the first program, when searching for the n-th program at the final recording position, In shift register IC ₂ , only the potential at the output terminal of the nth digit is set to low (L) level by an external operation to search for the program (operating the key corresponding to n on the keyboard to specify the program search). (The potentials of all other output terminals are at high level), and only the light emitting diode LED _o lights up, and it is stored that the nth program from the current location will be searched. Note that the key numbers on the keyboard mentioned above indicate the difference between the program number at the current location and the number of the program to be searched. For example, if the current program is (n-3), operating the "3" key will return n. The search for the program is specified. Here, each output terminal corresponding to 1 to (n-1) digits

As described above, the potential in [Equation] is at a high (H) level, and each of the light emitting diodes LED ₁ to LED _o-1 does not light up. SW ₁ is a power switch, SW ₂ is a start switch for starting a program search, and the internal mechanism of the tape recorder is set to drive the magnetic tape at high speed. When power switch SW ₁ is closed,
A positive DC power supply +B is applied to the brushes of the DC motor M to drive the DC motor M. However, when the start switch SW ₂ is closed, the DC voltage is applied to the resistor.
The voltage is applied to the base electrode of the npn transistor Q ₂ through R ₂ , and since the emitter electrode of this transistor Q ₂ is grounded and its collector electrode is connected to the base electrode of the transistor Q ₁ , this transistor Q ₂ is conductive. Therefore, transistor _Q1 becomes non-conductive. The emitter electrode of this transistor Q ₁ is grounded, and the collector electrode is connected to one end of the resistor R _s , and the other end of the resistor R _s whose one end is grounded is connected to the resistor r s . The other end of _s is a DC motor M
Since both are connected to the drive speed control voltage application terminal of the DC motor M, the transistor Q ₁ becomes non-conductive, and as a result, the resistor R _s is connected to the application terminal of the DC motor M.
The DC motor M starts to drive at the first type of high speed, that is, faster than the normal fast forward or rewind speed, and at the same time the magnetic tape T also starts to drive in accordance with this drive speed. begins to be Next, when the magnetic tape T starts to be driven at the first type of high speed, a signal related to the unrecorded portion intervening between the programs is sent to the shift register through the magnetic head H and the output part of the detection circuit _IC1 .
Input section of IC ₂

[Formula] begins to be applied one after another, and the low-level potential at the output terminal of shift register IC ₂ is sequentially directed to the output terminal from.
Moving. Then, the light emitting diode turns on and off in accordance with the movement of the low-level potential.
When the potential at the output terminal of the shift register IC ₂ changes from a high level to a low level, the only program to be skipped is the (n-1)th program until the nth program to be searched. At this time, since the potential appearing at the output terminal of shift register IC ₂ is at a low level, it is passed through resistor R ₇ connected to this terminal.
Due to this low level potential, the potential applied to the base electrode of transistor Q ₄ is reduced, and this transistor Q ₄ becomes conductive. Due to the conduction of the transistor _Q4 , the voltage of the DC power supply +B passes through the power switch _SW1 , the starting switch _SW2 , each electrode of the emitter collector of the transistor _Q4 , and the resistor _R8 , and conducts the transistor _Q5 . That transistor Q ₅ to the extent that you get
is applied to the base electrode of When this transistor _Q5 becomes conductive, the time constant of the time constant circuit A for detecting the unrecorded portion between programs during the first type of high-speed driving is changed from the time constant consisting of the resistor _R9 and the capacitor _C2 . , the time constant becomes longer for detecting unrecorded portions between programs during the second type of high-speed driving. That is, the time constant of the time constant circuit A is changed by the conduction of the transistor _Q5 to the resistor _R9 and the capacitor.
It consists of C ₂ and C ₃ . Furthermore, due to the conduction of the transistor Q ₄ , a DC voltage is also applied to the base electrode of the transistor Q ₃ through the resistor R ₄ , so that this transistor Q ₃ is also rendered conductive. When transistor Q ₃ becomes conductive, the potential at the base electrode of transistor Q ₂ decreases, making transistor Q ₂ non-conductive, and as a result, the voltage at the base electrode of transistor Q ₁ increases, making transistor Q ₁ conductive, One end of the resistor r _s is grounded. The driving speed of the DC motor M is determined by grounding this resistor r _s .
A second type high speed drive state (lower drive than the first type high speed drive, corresponding to normal fast forward or rewind drive) is entered, and the magnetic tape T also begins to be driven at the second type high speed. The first type of high-speed drive is a higher drive than the second type of high-speed drive, and the first to (nth)
The magnetic tape is driven at high speed by the first type of high speed drive up to the -1)th program, and the magnetic tape is driven by the second type of high speed drive for the (n-1)th program. When a non-recording section is detected between the (n-1)th program and the n-th program by skipping the (n-1)th program, all potentials from the output terminal of the shift register IC ₂ are It becomes high level, and the potential of the output terminal changes from high level to low level. At this time, the light emitting diodes LED ₁ to LED _o are all in a non-lighting state. Output terminal 0 of shift register IC ₂
When the potential at the base electrode of the pnp transistor Q6 decreases through the resistor _R10 , the potential at the base electrode of the pnp transistor _Q6 also decreases, so that the transistor _Q6 becomes conductive and the npn
Transistor _Q7 also conducts, so the transistor
The solenoid S inserted and connected between the collector electrode of Q ₇ and the DC power line l is energized, and this solenoid S sets the internal mechanism of the tape recorder from the second type high-speed drive state to the automatic playback state. do. However, even if the starting switch SW ₂ is opened by the operation of the solenoid S, the DC motor M is still in a conductive state because the voltage is applied to the base electrode of the transistor Q ₁ . That is, it continues to be rotated at the normal fast forward or rewind speed. However, the start switch SW ₂
However, even if the electric motor is driven at high speed, the solenoid S causes the internal mechanism of the tape recorder, such as the pinch roller and capstan to pinch the magnetic tape, and various deceleration means to operate. , the magnetic tape T is driven to run at a normal playback speed. Next, the time constant circuit A will be explained. When we consider that the magnetic tape is being driven at the second type of high-speed running, the running speed of the magnetic tape T during playback is v _p , and the unrecorded portion between the programs on the magnetic tape is magnetic during playback. If the time for passing through head H is _tp , and the second type high speed running speed of the magnetic tape is set to n times the running speed during playback, then the above-mentioned unrecorded portion during second type high speed running is transferred to the magnetic head. The time t _ho that H passes is t _p/o
becomes. Then, if the first type high speed running speed is set to m times the second type high speed running speed, the time t _hn for the magnetic head H to pass through the above-mentioned non-recording area is t _p
/no . Therefore, in the above embodiment, in the process of searching for the nth program, 1 to (n-
1) The passing time of each unrecorded part when the magnetic head passes through the th program is t _ho , (n-1)
_The passing _{time of} the unrecorded part between _the
It is necessary to change the time constant formed by the combination of each element of capacitors C ₂ and C ₃ . Therefore, 1 to (n
Regarding the unrecorded portion between each program up to -1), the unrecorded portion is detected using a time constant consisting of a resistor _R9 and a capacitor _C2 . This time constant is set to circuit IC ₁ for the expected unrecorded portion during recording within the program, and for the unrecorded portion between the 1st to (n-1)th programs, the circuit
This is sufficient to generate a predetermined signal from IC ₁ . Then, regarding the detection of the unrecorded part between the (n-1)th and nth programs, since the transistor _Q5 conducts as described above, the resistor _R9
The unrecorded portion is detected using a time constant consisting of the capacitors C ₂ and C ₃ . This time constant also makes the circuit IC 1 insensitive to the expected unrecorded part during recording in the (n-1)th program, and makes the circuit IC ₁ insensitive to the unrecorded part between the (n-1)th and nth programs. As for the recorded portion, it is sufficient for the circuit IC ₁ to generate a signal related to the detection of the unrecorded portion. Regarding the expected unrecorded parts during recording within all programs and the unrecorded parts between each program, regardless of the speed of the magnetic tape, the unrecorded parts of both can be distinguished and the unrecorded parts of the latter can be distinguished. It is possible to set the constant of the time constant circuit A to be fixed so that only the portion of the time constant can be detected. Next, a description will be given of the capacitor _C1 connected between the collector electrode of the transistor _Q4 and the ground. When the unrecorded portion between the (n-2)th program and the (n-1)th program is detected, the potential of the output terminal of shift register IC ₂ becomes low level, and as mentioned above, the DC The rotation speed of electric motor M begins to decrease, and the (n-1)th program and n
When the unrecorded portion between the th program is detected, the potential at the output terminal of the shift register IC ₂ becomes a low level and the rotation speed of the DC motor M is maintained as it is, but due to the internal mechanism of the tape recorder. , the magnetic tape T is driven to run at the reproduction speed. However, at this time, since the potential of the output terminal of shift register IC ₂ is at a high level, the tape recorder is not activated by solenoid S even though both transistors Q ₄ and Q ₃ are already non-conductive. Because there is a slight response delay in the internal mechanism,
There is a period of time when starting switch SW ₂ is not in the open state. During this period, the transistor
Since Q ₂ is still conducting and therefore transistor Q ₁ is non-conducting, the resistor r _s is not grounded, and the rotational speed of the DC motor M is in the first type high speed driving state, and the magnetic The tape attempts to run at a higher speed. Therefore, during this time period, magnetic tape T
Since the internal mechanism of the tape recorder is not operating, the tape recorder is driven at the first type of high speed, and there is a possibility that the tape recorder will be bitten into the beginning of the recording of the nth program. Therefore, the capacitor _C1 eliminates the existence of such a time period, and the shift register
Even if the output terminal of IC ₂ becomes high level and the transistor Q ₄ becomes non-conductive, the conductive state of the transistor Q ₃ is maintained for that period of time by discharging the charge in the capacitor C ₁ , and the starting switch is activated. Until SW ₂ is opened, that is, for the response delay time of the internal mechanism of the tape recorder, transistor Q ₃ is turned on, transistor Q ₂ is turned off, and transistor Q ₁ is turned on, and the rotational speed of DC motor M is controlled. By maintaining the second type of high-speed driving state, (n-
1) It is possible to accurately detect the unrecorded portion between the th program and the nth program. In the embodiment of this invention, the high-speed running speed of the magnetic tape is changed by changing the rotational speed of the DC motor M. While the rotation of the motor M is kept constant, the resistor r _s is connected to the solenoid. It is also possible to change the high-speed running speed of the magnetic tape during program retrieval by mechanical means such as replacing the magnetic tape with idlers of different diameters and controlling the energization of this solenoid. be. It is also possible to use other variable impedance elements, such as fixing the capacitance of the capacitor of the time constant circuit A and changing the resistance value of the resistor. As explained above, according to the present invention, the program search can be performed at a first type of high speed that is faster than the fast forwarding or rewinding speed, and a second type of program search that is slower than the first type of high speed and faster than the playback speed. Since the program search is performed at high speed, the program search can be performed in an extremely short time. Furthermore, the first
Since the non-signal portion is detected using the first time constant and the second time constant, the program can be searched extremely accurately, and a special signal for control can be recorded between programs on the recording medium. This has the advantage that recording media recorded with other devices can be used without any problems.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the invention. H: Magnetic head, IC ₁ : Detection circuit, IC ₂ : Shift register, M: DC motor, S: Solenoid,
SW ₁ : Power switch, SW ₂ : Program search start switch.

Claims (1)

[Scope of Claims] 1. A program capable of searching for a search target program in the recording medium while the recording medium is being driven at high speed by a drive means, and at the time of starting the search for the search target program. The time required from the time to the end of the search is sequentially divided into a first search period and a second search period, and during the first search period, the recording medium is moved at a first type of high speed that is faster than the fast forward or rewind speed. and the recording medium is driven at a second type of high speed that is lower than the first type of high speed and faster than the playback speed during the second search period, a first time constant corresponding to the first type of high speed for detecting a non-recorded portion in the recording medium during the search period; and a first time constant for detecting the non-recorded portion in the recording medium during the second search period. and a second time constant corresponding to a second type of high speed. 1st every time detect based on constant
signal generating means for generating a second detection signal when a non-recorded portion in the recording medium is detected based on the second time constant during the second search period; and the signal generating means for generating a second detection signal. counting means for counting the number of unrecorded portions up to the program to be searched based on a first detection signal from the program and generating a speed switching signal when the number of programs to be skipped becomes less than a predetermined value; Based on the speed switching signal, the driving means switches the speed of the recording medium from the first type of high speed to the second type of high speed, and also changes the time constant of the time constant circuit in the signal generating means to a first time constant. switching means for switching to a second time constant corresponding to the second type of high speed, the program position to be searched based on the second detection signal obtained from the signal generating means during the second search period. A program search device characterized in that a desired operating state is achieved by: