JPS6021410B2 - Tape recorder control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit for electronically controlling a mechanical section of a tape recorder.

Kameko control type tape recorders have the feature that, unlike conventional mechanical control types, additional functions can be easily added, and additional functions such as automatic repeat play are a major selling point.

When performing automatic repeat performance, if the tape ends while the mechanism is in the playback state, the mechanism goes into the rewind state, and if the tape ends while in the rewind state, the mechanism goes into the playback state. However, if the signal timing is not adjusted at this time, there is a risk of oscillation occurring within the control circuit, so some capacitors are used to ensure stable operation.

FIG. 1 shows the circuit diagram of the slave. In FIG. 1, input switches 1 to 6 are switches for the user to operate the tape recorder, flip-flops 7 to 11 are for storing states designated by input signals, plungers 30, 31 is for mechanically driving the mechanism section.

In the case of reproduction, when the input switch 3 is closed, the flip-flop 9 is set, the transistor 28 is turned on through the NOR gate 21, and the plunger 30, which has the function of advancing the head plate, is operated. Although the mechanical part is not shown, a head and a pinch roller are provided on the head slope, and when the head plate moves forward, the head contacts the tape, the pinch roller is attached to the capstan, and the mechanical part returns to the playback state. Become. In the case of rewinding, when the input switch 5 is closed, the flip-flop 11 is set;
The transistor 29 is turned on through the Noah gate 22 and the inverter 23, and the plunger 31, which has the function of releasing the brake that stops the rotation of the reel, operates.
At the same time, the motor that drives the reel starts rotating and enters the rewinding state. In the case of fast forwarding, the flip-flop 10 is set by the input switch 4, and the plunger 31 is also operated, resulting in a fast forwarding state. The input switch 6 is a stop switch, and when this switch is closed, all the flip-flops 7 to 11 are reset, and the machine section is brought to a stop state. Input switch 1 and flip-flop 7 are used to set the recording state, and input switch 2 and flip-flop 8 are used to temporarily stop the recording. Note that signals for displaying the status of the control circuit and signals for switching between recording and playback of the signal system are output from the flip-flops 7 to 11, but these are not directly related to the present invention and will therefore not be discussed here. It is omitted in Figure 1. The monomulti 33 is triggered by the output of a tape end detection device 32, such as a device that uses a phototransistor and a lamp to detect when the tape has been wound up to the translucent leader tape.

The changeover switch 36 is a switch for switching automatic repeat performance on and off, and when the switch is turned on the A side, automatic repeat performance is off.
If the switch is on side B, it is on. If the automatic repeat performance is off, the control circuit will automatically stop when the tape ends. That is, the signal from the mono multi 33 that is triggered at the end of the tape is
This has the same effect as closing the input switch 6, all flip-flops 7 to 11 are reset, and the mechanical section is brought to a halt. When automatic repeat performance is on, the next state to move to 0 is determined depending on the state of the control circuit. If the control circuit is currently in the regeneration state, only the flip-flop 9 is set.

At this time, when the tape ends and the monomulti 33 is triggered, the output is transmitted to the NOR gates 43-45. Then, only Tanoa gate 43 outputs a high level output,
Transistor 52 is turned on. The transistor 52 is
It is connected to the input switch 5, and when the transistor 52 is turned on, it has the same effect as if the input switch 5 were closed, and the mechanism section is in the rewinding state. When the control circuit is in the rewind state, the transistor 54 is turned on via the NOR gate 45 by the trigger of the monomulti 33,
By the same action as when the input switch 3 is closed, the mechanism automatically changes to the regeneration state.

Similarly, when the control circuit is in a fast forward state, the transistor 53 is turned on and the mechanical section is automatically stopped. A timing capacitor 35 and a resistor 34 that determine the time constant of the monomulti 33, and resistors 37-39 and capacitors 40-34 that delay the inputs of the NOR gates 43-45.
42 is used to synchronize the timing of signals of each part.

The pulse width of monomulti 33 is the same as that of transistor 5.
This is the time during which transistors 2 to 54 are turned on, and the pulse width must be long enough to prevent the control circuit from malfunctioning, taking into account the response speed specific to the transistor. On the other hand, the time constants of the resistors 37 to 39 and the capacitors 40 to 42 must be sufficiently larger than the pulse width of the monomulti 33. Now, if the tape ends while it is in the playback state, Noah Gate 4
Both inputs 3 go low, turning on transistor 52, resetting flip-flop 9 and setting flip-flop 11, and the control circuit enters the unwinding state. However, when the control circuit goes into the rewind state, the circuit that automatically puts it into the playback state operates, turning on the transistor 54, and generates a signal that puts the control circuit into the playback state. A loop is formed between the two, resulting in an oscillation state. Resistors 37-39 and capacitors 40-42
The delay circuit formed by is for cutting this loop, and until the output pulse of the monomulti 33 disappears,
This is for delaying the signals of flip-flops 9-11. In the circuit example shown in FIG. 1, automatic repeat Z and performance functions can be added relatively easily, and it is suitable for forming a control circuit with discrete components.

However, the above-mentioned capacitor is indispensable for obtaining stable operation, and is not suitable for implementing the above-mentioned control circuit into an IC. Z An object of the present invention is to provide a control circuit for a tape recorder which does not require a capacitor and which provides stable operation and is suitable for IC implementation. A feature of the present invention is that by using edge-triggered flip-flops, a control circuit for automatic repeat performance is constructed so that stable operation can be obtained without oscillation even without the use of a capacitor. As a reset signal, the output signal of the time delay circuit, which is essential for controlling the mechanism of an electronically controlled tape recorder, is used, and it also includes a memory function that operates in conjunction with the tape counter. The reason lies in the fact that it was realized.

The present invention will be explained in detail below with reference to an embodiment circuit diagram shown in FIG.

In Fig. 2, the terminals A, 口, C, etc. shown in Fig. 2 a and Fig. 2 b are respectively connected, and the terminals shown in Fig. 2 c The part surrounded by the dashed line is composed of an IC. Input switches 1 to 6 and flip-flops 7 to 11 in Figure 2
, and the decoder sections of these flip-flops are the same as the circuit of FIG. Inverters 55-57 and NOR gates 61-63 are added to combine the input signal from the automatic repeat performance circuit and the signal from the input switch. flipflop 67~7
2. The portion consisting of the inverters 78 to 80, the agates 86 and 87, the NAND gate 89, the resistors 97 and 98, the transistor 99, and the external charging circuits 103 and 104 is connected to the time required to drive the mechanism. This is a circuit for making. One of the greatest advantages of an electronically controlled tape recorder is that it can move from any state to the next with the touch of a button, and in order to perform such operations without damaging the tape, The time delay circuit described above is required. External resistor 107 and capacitor 108
The fin circuit consisting of is for detecting the end of the tape, and when the tape is running normally, it is charged by pulses sent from the rotation detection bag straight 105 of the reel. When the tape ends and the reel stops rotating, the capacitor 108 is discharged and the potential drops, and a signal that the tape has ended is sent to the circuit through the inverter 81. Transistor 10 when stopped or temporarily stopped
It is charged through 2. When the tape end signal is input, the flip-flop 73 is set, and the state of the circuit at the o moment is stored in the D-type flip-flops 75 to 77 through the /Agate 88.

That is, the flip-flop 75 is in the playback or recording state, and the flip-flop 75 is in the fast-forward state.
6 and is in the rewind state, the flip-flop 77
are set respectively. NOR gates 90 to 95 are decoder sections, which determine the next state to be moved to according to the states of flip-flops 75 to 77, and send the signals to the decoder section shown in FIG.
Output to the basic part of the control circuit of the section. These signals are
The signals from the operation switches are combined with the signals from the operation switches and set to 0 by the Noah gates 61 to 63. Flip Flop 75-77
is a D-type flip-flop which stores the state of the control circuit at the moment the tape end signal is input. Therefore, even if the state of the control circuit changes due to a signal from the decoder, the output of the decoder does not change and oscillation does not occur. The switch 113 is for turning on/off the automatic repeat performance, and when it is closed, the automatic repeat performance is turned off. If automatic repeat play is on and the state immediately before the tape end signal is input is playback or recording, the output of the Noah gate 92 in the decoder is
・It reaches the level and outputs a rewind signal to the control circuit. When automatic repeat performance is on and the previous state is rewind, the output of /Agate 90 becomes high level and outputs a reproduction signal to the control circuit. When the automatic repeat performance is off and when the previous state was fast forward, the output of the Noah gate 94 becomes high level, sends a stop signal to the control circuit, and the circuit automatically stops. The counter interlocking switch 109 is used to perform a memory function, and is closed when the display of the tape running counter reaches 999. When the counter interlocking switch 109 is closed, the flip-flop 74 is set, and the O-type flip-flop 74 is set as in the case of automatic repeat play.
5 to 77, the immediately previous state of the control circuit is stored. In the decoder, when the previous state is rewind and automatic repeat performance is on, the NOR gate 91 becomes high level and outputs a reproduction signal to the control circuit. If the previous state is rewinding and the automatic repeat performance is off, the Noah gate 93 becomes the /. level and outputs a stop signal to the control circuit. In cases other than the above, the decoder does not output a signal. When the flip-flops 73 to 77 are set by a tape end signal or a signal from the counter interlocking switch 109, a circuit for creating a timer is activated, and after a period of about 0.5 to 2 seconds has elapsed, the flipflops 73 to 77 are set. All flip-flops 73-77 are reset.

Furthermore, when the tape end signal is input, the external capacitor 108 is charged by the transistor 102 while the time delay circuit is operating. When automatically changing from playback to rewinding or vice versa due to automatic repeat performance, the mechanical section is stopped while the time delay circuit is operating, and during that time the external capacitor 108 is connected to the transistor 102. After charging, all flip-flops 67-T7 of the time delay circuit and automatic repeat playing circuit are reset, the signal from the decoder is also stopped, and the next new state is entered. Second
In the example shown in the figure, only the on/off switching of the automatic repeat performance is performed, but by increasing the number of input terminals it is also possible to switch more detailed functions, in which case the circuit state is already memorized. Therefore, all you need to do is change the decoder part.

Furthermore, there may be various methods of detecting the end of the tape other than the one shown in the example of FIG. As described above, according to the present invention,
With the exception of the capacitors attached to the tape end signal input terminal and the counter interlocking switch input terminal, the only external capacitors required are the timing capacitors for the time delay circuits that are essential for controlling the mechanism. No special capacitors are required for performance. Therefore, when this type of control circuit is integrated into an IC, it is possible to reduce the number of external capacitors and the number of pins for the external capacitors, and it has the practical effect of allowing extremely efficient integration.

[Brief explanation of the drawing]

Fig. 1 is a control circuit diagram of a conventional tape recorder, and Fig. 2 is a circuit diagram of an embodiment of a control circuit of a tape recorder according to the present invention. The circuits are combined to form one control circuit. 1-6...Input switch, 7-11...
・RS type flip-flop, 12, 13...Nor gate, 14...NAND gate, 15-17...Inverter,
18~20''''Nand gate, 21,22...Noah gate, 24~27...Resistance, 28,29...
...Transistor, 30, 31...Plunger, 55-
60...Inverter, 61-66.../Agate, 67
~69...D type flip-flop, 70~74...
...RS type flip-flop, 75-77...D-type flip-flop, 78-85...Inverter, 86-88
...Noah Gate, 89...Nand Gate, 90-95...
...Noah gate, 96...Voltage detector, 97,9
8...Resistance, 99...Transistor, 100,10
1... Resistor, 102... Transistor, 103... Timing resistor, 104... Timing capacitor, 1
05... Reel rotation detector, 106....・．． Diode, 107... Discharge resistor, 108...
...・Capacitor, 109...Counter Ryojin switch, 1
10, 111...Resistor, 112...Capacitor, 113...Automatic repeat performance on/off switch, 1 14...IC circuit. Oh 4 years old 24 Buddha) Oh 24 (also,

Claims (1)

[Claims] 1. It has playback, fast forward, and rewind switches 3, 4, and 5, and a plurality of flip-flops corresponding to each of the switches, and the flip-flops corresponding to the closed switches are set and the closed switches are stored. a first flip-flop group 9, 10, 11, and a plunger group 30, which has a plurality of plungers for mechanically driving the mechanism, and a plunger corresponding to a closed switch is driven.
, 31, a first flip-flop 73 that is set by a device that detects the end of the tape, and a second flip-flop that is set by a switch that opens and closes in conjunction with a tape counter that displays the amount of tape travel. 74 and
a plurality of flip-flops corresponding to the first and second flip-flops and the plurality of flip-flops connected to the first flip-flop group; The set output of the first or second flip-flop when there is no position is used to set the first flip-flop.
a second flip-flop group 75-77 for setting and storing the memory state of the flip-flop group; It calculates the outputs of the second flip-flop group, outputs the same control signal as if a switch other than the closed switch was closed, and supplies the control signal to the first flip-flop group to control the other switch. Logic circuits 90 to 95 for setting flip-flops corresponding to the flip-flops connected to the second flip-flop group operate when the flip-flops of the second flip-flop group are set, and after a predetermined time elapse, the logic circuits 90 to 95 set the flip-flops corresponding to the first and second flip-flops. and time delay circuits 89, 80, 97 to 99, 103, 104 for resetting all the second flip-flop groups.