JPH0682476B2 - Switching circuit of magnetic reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a circuit for switching two magnetic read-out devices, for example, a video tape recorder, so as to alternately put them in a reproducing state.

<Prior Art> Conventionally, as a switching circuit as described above, for example, there is one as shown in FIG. This is flip-flop 1
Assuming that the reproducing operation of the video tape recorder (hereinafter referred to as VTR) 2 is completed, the VTR 2 supplies a signal "1" to the S input terminal of the flip-flop 1. As a result, the pulse generation circuit 3 operates and supplies a pulse signal for starting the reproducing operation to the VTR 4. This causes the VTR4 to start playing. At this time,
The VTR2 automatically rewinds. When the reproduction of VTR4 ends, VTR4 supplies the signal of "1" to the R input terminal of flip-flop 1, and the Q output becomes "0".
The output becomes "1", the pulse generation circuit 5 operates, and VTR2
Is supplied with a pulse signal for starting the reproducing operation. At this time, since the rewinding of VTR2 has already been completed, VTR2 starts the reproducing operation, and VTR4 automatically starts the rewinding operation. When the reproducing operation of VTR2 is completed, VTR2 supplies the signal of "1" to the S input terminal of flip-flop 1. At this time, the VTR 4 has completed the rewinding operation, and thereafter, the VTRs 2 and 4 perform the reproducing operation alternately in the same manner.

<Problems to be Solved by the Invention> Such a switching circuit is used, for example, in a hotel or inn when supplying a video signal to a television receiver in each guest room. Upon completion, the other VTR can immediately start the reproducing operation, so that the video signal can be supplied to each television receiver without interruption. However, in this switching circuit, if one of the two VTRs fails and you want to continue the playback operation with only the other one, or only the video tape on one of the two VTRs. There was a problem that this could not be dealt with in the case of continuous reproduction.

<Means for Solving Problems> The present invention relates to first and second magnetic reproducing devices that are in a reproducing state when a reproducing instruction pulse is supplied, and first and second magnetic reproducing devices.
When none of the magnetic reproducing devices of the
And a reproduction signal detection circuit that generates a reproduction detection signal that is in the second state when one of the first and second magnetic reproduction apparatuses is in the reproduction state, and the reproduction operation of the first magnetic reproduction apparatus. In response to the reproduction operation of the second magnetic reproducing device, the second magnetic reproducing device is switched from the first magnetic reproducing device to the second magnetic reproducing device, and from the second magnetic reproducing device to the first magnetic reproducing device. To the first magnetic reproducing device side in response to the reproducing operation of the first magnetic reproducing device and the reproducing operation of the second magnetic reproducing device. A second switching unit that switches from the first magnetic reproducing apparatus side to the second magnetic reproducing apparatus side in response to the operation, and starts the generation of the reproduction instruction pulse according to the first state of the reproduction detection signal. The reproduction is performed according to the second state of the reproduction detection signal. A pulse generating circuit for stopping the generation of the shown pulse becomes the first state when either the first and second magnetic reproducing apparatus is in the rewinding state, first and second
Rewinding detection circuit that generates a rewinding detection signal that is in a second state when both of the magnetic reproducing devices are in a non-rewinding state, and the reproduction detection signal is in the first state, and the rewinding detection signal is Is a second state, a counter that counts the reproduction instruction pulse and that generates a count signal that is in the second state when the count value reaches the predetermined value and is in the first state until the count value reaches the predetermined value. First gate means for supplying the reproduction instruction pulse to the first switching section when the count signal is in the first state, and the reproduction to the second switching section when the count signal is in the second state. Second gate means for supplying an instruction pulse.

<Operation> According to the present invention, since the reproduction detection signal of the reproduction signal detection circuit is in the first state 2 when both the first and second magnetic reproduction devices are not performing the reproduction operation, the pulse generation circuit Generates an instruction pulse. At this time, if both the first and second magnetic reproducing devices are in the non-rewinding state, the rewinding detection signal of the rewinding detection circuit becomes the second state, and the counter starts counting the reproduction instruction pulse. The counter continues to generate the count signal in the first state until the count value reaches the predetermined value. Therefore, the reproduction instruction pulse is supplied to the first switching section via the first gate means, and then the first switching section is started. And the first magnetic reproducing device starts to operate. As a result, the reproduction detection signal of the reproduction signal detection circuit becomes the second state, and the reproduction instruction pulse is stopped. The first switching unit is switched from the first magnetic reproducing device side to the second magnetic reproducing device side, and the second switching unit is switched from the second magnetic reproducing device side to the first magnetic reproducing device side. To be

When the reproduction of the first magnetic reproducing device is completed, the reproduction detection signal of the reproduction signal detecting circuit becomes the first state, and the reproduction instruction pulse is generated. At this time, since the rewinding detection signal is in the first state, the counter does not count, and the generation instruction pulse is supplied to the second magnetic reproducing device via the first gate means and the first switching unit. The second magnetic reproducing device is activated.
At this time, the first switching section is switched from the second magnetic reproducing apparatus side to the first magnetic reproducing apparatus side, and the second switching section is switched from the first magnetic reproducing apparatus side to the second magnetic reproducing apparatus side. Can be switched.

For example, in this state, when the first magnetic reproducing device becomes unreproducible and the reproduction of the second magnetic reproducing device ends, the pulse generating circuit generates a reproduction instruction pulse. At this time, since the second magnetic reproduction device is rewinding, the counter does not count, and the reproduction instruction pulse is supplied to the first magnetic reproduction device through the first gate means and the first switching unit. However, since the reproduction is impossible, the reproduction operation is not performed. When the rewinding of the second magnetic reproducing device is completed, the counter starts counting the reproduction instruction pulse and counts a predetermined value,
When the counter generates the count signal in the second state, the reproduction instruction pulse is supplied to the second magnetic reproducing device through the second gate unit and the second switching unit, and the second magnetic reproducing device performs the reproducing operation. To start.

<Effect> As described above, according to the present invention, when the reproducing operation is not started even if the reproducing instruction pulse is supplied to the magnetic reproducing apparatus to be reproduced next by a predetermined number, the counting means generates the switching signal. Then, the supply destination of the reproducing instruction pulse is switched to the magnetic reproducing apparatus which has just finished the reproducing operation, and this magnetic reproducing apparatus starts the reproducing operation again, so that one magnetic reproducing apparatus fails and the remaining 1 Even when the reproducing operation needs to be performed by only one unit, or when only one magnetic reproducing device is desired to be reproduced, only one unit can be smoothly continuously reproduced. Moreover, in order to perform such an operation, in the present invention, the reproduction signal detection circuit, the first switching unit, the second switching unit, and the rewinding detection circuit are provided for the two magnetic reproduction devices. , Counter and first
Since only one gate means and one second gate means need be provided, the configuration can be simplified.

<Embodiment> FIGS. 1 to 3 show an embodiment of the present invention. In this embodiment, two VTRs 10 and 12 are alternately reproduced, and when any one of them is stopped, the remaining one is continuously reproduced.

The VTRs 10 and 12 are configured to start a reproducing operation when a reproducing instruction pulse is supplied through the switching means 14 which will be described later. Whether the VTRs 10 and 12 are performing a reproducing operation is determined by the reproducing operation. It is detected by the signal detection circuit 16.
This reproduction signal detection circuit 16 produces an output "1" when both VTRs 10 and 12 are not performing reproduction operation,
Output terminal 16a that produces an output "0" when any of the VTRs 10 is performing a reproducing operation, and output terminal 16b that produces an output "1" when the VTR 10 is performing a reproducing operation and the VTR 12 performs a reproducing operation. Output terminal 16 that produces output "1" when
have c.

The output of the output terminal 16a of the reproduction signal detection circuit 16 is supplied to the pulse generation circuit 18. The pulse generation circuit 18 generates a reproduction instruction pulse having a predetermined frequency when the start signal input terminal 18a is supplied with a "1" start signal and the output terminal 16a is supplied with an "1" output signal. Start.

A rewinding detection circuit 20 is also provided for the VTRs 10 and 12, and when one of the VTRs 10 and 12 is in a rewinding operation, an output signal "1" is generated at its output terminal.

The reproduction instruction pulse from the pulse generation circuit 18 is a NOR gate.
An OR gate 26 which is supplied to one input of 22 and receives the output of the output terminal 16a of the reproduction signal detecting circuit 16 inverted by the inverter 24 and the output of the rewinding detecting circuit 20 as the other input. Output is being supplied. The output of the NOR gate 22 is supplied to the clock terminal of the pulse counter 28. Since the output of the NOR gate 22 is "0" when one input is "1", the OR gate 22 is
Only when the output of 26 is "0", that is, the rewinding detection circuit 20
Detects that one of the VTRs 10 and 12 is not rewinding,
Further, when the reproduction signal detection circuit 16 detects that neither of the VTRs 10 and 12 is performing the reproduction operation, the reproduction instruction pulse is supplied to the clock terminal of the pulse counter 28.

The output signal of the output terminal 16a of the reproduction signal detection circuit 16 inverted by the inverter 24 is also supplied to the clear terminal of the pulse counter 28. The pulse counter 28 is configured such that when the signal input to the clear terminal is "1", the count value is cleared, and when the signal is "0", the count starts. It is cleared when any one starts the reproducing operation. Further, the pulse counter 28 is configured to generate an output signal "1" when the count value reaches a predetermined value. This predetermined value is, for example, VTR10, 1 of the reproduction instruction pulse.
The reason why the regeneration operation does not occur even when the supply to the 2 is continued is determined by the time at which it can be determined that there is a failure and the frequency of the regeneration instruction pulse.

The reproduction instruction pulse of the pulse generation circuit 18 is supplied to one input of the AND gates 30 and 32 of the switching means 14. Further, the other input of the AND gate 30 is supplied with the output signal of the pulse counter 28 via the inverter 34 and the AND gate 32.
The output of the pulse counter 28 is directly supplied to the other input of the. Therefore, the output of AND gate 30
When the output of the pulse counter 28 is "0", a reproduction instruction pulse is generated, and when the output of the pulse counter 28 is "1", the reproduction instruction pulse is generated in the AND gate 32.

The output of the AND gate 30 is supplied to the OR gates 36, 3 in the switching means 14 via the relay contact 35 of the latch relay in the switching means 14.
8 is switched and supplied, and similarly, the output of the AND gate 32 is switched and supplied to the OR gates 36 and 38 via the relay contact 40.
The relay contacts 35 and 40 are output terminals 16b of the reproduction signal detection circuit 16.
When an output signal "1" is generated at, that is, when the VTR 10 starts the reproduction operation, the relay drive circuit 42 of the latch relay energizes the drive coil 44, and the output side of the AND gate 30 from the side of the OR gate 36. Switch to 38 side and AND gate 32
The output side of is switched from the OR gate 38 side to the 36 side. In addition, the relay contacts 35 and 40 cause the relay drive circuit 46 to energize the drive coil 48 when the output "1" is generated at the output terminal 16c of the reproduction signal detection circuit 16, that is, when the VTR 12 starts the reproduction operation. Then, the output side of the AND gate 30 is switched from the OR gate 38 side to the 36 side, and the output side of the AND gate 32 is switched from the OR gate 36 side to the 38 side. The output of OR gate 36 is supplied to VTR10 and the output of OR gate 38 is VTR12.
Is supplied to. Therefore, the output of the AND gate 30 is supplied to the VTR 10 or 12 via the OR gate 36 or 38 depending on the switching state of the relay contact 35, and similarly the AND gate 3
The output generated at 2 is supplied to the VTR 10 or 12 via the OR gate 36 or 38 depending on the switching state of the relay contact 40.

Next, the alternate reproduction operation of this circuit will be described with reference to FIG. At this time, the VTRs 10 and 12 are not performing the reproducing operation, and therefore, the output terminal 16a of the reproducing signal detecting circuit 16
The output signal of "1" is generated at the output of the AND gate 30 and the output signal of the AND gate 30 is transmitted to the VT via the OR gate 36 by the relay contact 35.
The state of being supplied to R10 and the output of AND gate 32 is
It is assumed that the relay contact 40 supplies the VTR 12 through the OR gate 38.

In this state, when the start signal of "1" is supplied to the start signal input terminal of the pulse generation circuit 18 as shown in FIG. 2 (a), the reproduction signal detection circuit 16 is already output as shown in FIG. 2 (b). Since the signal of "1" is supplied from the output terminal 16a of the pulse generation circuit 18, the pulse generation circuit 18 starts the generation of the reproduction instruction pulse as shown in FIG.

The reproduction instruction pulse is supplied to the AND gates 30 and 32 and also to one input of the NOR gate 22.
At this time, the output "1" of the output terminal 16a of the reproduction signal detection circuit 16 inverted by the inverter 24 is the OR gate 26.
Since it is supplied to the other of the NOR gate 22 via the, the reproduction instruction pulse is generated at the output of the NOR gate 22 and the reproduction instruction pulse is supplied to the clock terminal of the pulse counter 28 as shown in FIG. It The clear terminal of the pulse counter 28 is supplied with "0" obtained by inverting the output "1" of the output terminal 16a of the reproduction signal detection circuit 16 by the inverter 24, so that the pulse counter 28 counts the reproduction instruction pulse. However, since the predetermined value has not been reached yet, the output of the pulse counter 28 is “0” as shown in FIG. Since this output "0" is inverted by the inverter 34 and supplied to the AND gate 30, a reproduction instruction pulse is generated at the output of the AND gate 30, as shown in FIG. 35, is supplied to the VTR 10 via the OR gate 36. On the other hand, since the output "0" of the pulse counter 28 is supplied to the AND gate 32 as it is, the output of the AND gate 32 is "0", and the reproduction instruction pulse is not supplied to the VTR 12.

When the VTR 10 starts the reproduction operation due to the supply of the reproduction instruction pulse, this is detected by the reproduction signal detection circuit 16, and the output of the output terminal 16a becomes "0". As a result, the generation of the reproduction instruction pulse from the pulse generation circuit 18 is stopped. At this time, the clear terminal of the pulse counter 28 becomes "1" as shown in FIG.
Further, since the VTR 10 starts the reproduction operation, the output “1” is generated at the output terminal 16b of the reproduction signal detection circuit 16, the relay drive circuit 42 operates, and the drive coil 44 is energized. As a result, the relay contacts 35 and 40 are switched, so that the output of the AND gate 30 can be supplied to the VTR 12 and the output of the AND gate 32 can be supplied to the VTR 10.

Eventually, when the reproducing operation of the VTR 10 is completed, the VTR 10 automatically starts the rewinding operation, and the output of the rewinding detection circuit 20 becomes "1". At the same time, similarly to the above, the output of the output terminal 16a of the reproduction signal detection circuit 16 becomes "1", and the pulse generation circuit 18 starts the generation of the reproduction instruction pulse. At this time, since the output of the rewinding detection circuit 20 is "1", the output of the NOR gate 22 is "0", the reproduction instruction pulse is not supplied to the clock terminal of the pulse counter 28, and the pulse counter 28 is Although the clear terminal is "0", the reproduction instruction pulse is not counted. Therefore, the output of the pulse counter 28 is "0", the reproduction instruction pulse is generated at the output side of the AND gate 30, and is supplied to the VTR 12 via the relay contact 35 and the OR gate 38. As a result, when the VTR 12 starts the reproduction operation, the output of the output terminal 16a of the reproduction signal detection circuit 16 becomes "0", and the generation of the reproduction instruction pulse is stopped.
At the same time, the output terminal 16c becomes "1". This causes the relay drive circuit 46 to energize the drive coil 48 and the relay contact 3
5, 40 make the output of the AND gate 30 supplied to the VTR 10 via the OR gate 36 and the output of the AND gate 32 supplied to the VTR 12 via the OR gate 38.
Thereafter, the VTR 12 alternately performs the reproducing operation in the same manner.

Next, with reference to FIG. 3, a case where the VTR 12 cannot continuously perform the reproducing operation due to a failure or the like, and therefore the VTR 12 is continuously reproduced will be described. Since the VTR 12 cannot perform the reproducing operation due to a failure or the like, the VTR 10 can be continuously reproduced, but the description thereof will be omitted.

Now, the VTRs 10 and 12 are not performing the reproduction operation, and the output "1" is generated at the output terminal 16a of the reproduction signal detection circuit 16, but the pulse generation circuit 18 has the start signal input terminal "0".
Therefore, the regeneration instruction pulse is not generated, and the output of the AND gate 30 is transmitted to the VTR 10 via the relay contact 35 and the OR gate 36, and the output of the AND gate 32 is transmitted to the relay contact 4
0, it is assumed that the VTR 12 is supplied via the OR gate 38.

In this state, when the start signal becomes "1" as shown in FIG.
As shown in FIG. 5, a reproduction instruction pulse is generated, and the reproduction instruction pulse is supplied to the AND gates 30 and 32 and also to one input of the NOR gate 22. At this time, the other input of the NOR gate 22 is connected to the output terminal of the reproduction signal detection circuit 16.
Since the output "1" of 16a is inverted by the inverter 24 to be "0" and is supplied through the OR gate 26, the output of the NOR gate 22 has a reproduction instruction pulse as shown in FIG. Generated and supplied to the clock terminal of the pulse counter 28. At this time, since the output of the inverter 24, which is "0", is supplied to the clear terminal of the pulse counter 28,
The pulse counter 28 starts counting the reproduction instruction pulse, but since it has not reached the predetermined value yet, its output is
It is “0” as shown in FIG. Therefore, the output of the inverter 34 is "1", and a reproduction instruction pulse is generated at the output of the AND gate 30, and is supplied to the VTR 10 via the relay contact 35 and the OR gate 36 as shown in FIG. However, since the VTR10 does not perform the reproducing operation due to a failure or the like, the output from the output terminal 16a of the reproducing signal detecting circuit 16 is "1".
The reproduction instruction pulse continues to be generated, and the pulse counter 28 continues to count the reproduction instruction pulse. Eventually, when the count value of the pulse counter 28 reaches a predetermined value, the output of the pulse counter 28 becomes "1" as shown in (h) of the figure, and the output of the AND gate 30 becomes as shown in (j) of the figure. It becomes "0", and a reproduction instruction pulse is generated at the output of the AND gate 32 as shown in FIG. This is supplied to the VTR 12 via the relay contact 40 and the OR gate 38, which causes the VTR 12 to start the reproducing operation. This reproduction operation is detected by the reproduction signal detection circuit 16, the output of the output terminal 16a of the reproduction signal detection circuit 16 becomes "0", and the generation of the reproduction instruction pulse from the pulse generation circuit 18 is stopped. At the same time, the output terminal 16c of the reproduction signal detection circuit 16 has an output "1" because the VTR 12 has started the reproduction operation.
Occurs, the relay drive circuit 46 operates and energizes the drive coil 48, but the output of the AND gate 30 has already been applied to the relay contact 35,
The output of the AND gate 32 is supplied to the VTR 10 via the OR gate 36, and the output of the AND gate 32 is relay contact 40, OR gate 38
The relay contacts 35 and 40 do not switch because they are supplied to the VTR 12 via the.

Eventually, when the reproduction operation of the VTR 12 ends, the output of the output terminal 16a of the reproduction signal detection circuit 16 becomes "1" and the generation of the reproduction instruction pulse is started, and this reproduction instruction pulse is supplied to the AND gates 30 and 32. And is supplied to the NOR gate 22. Further, since the VTR 12 automatically starts the rewinding operation, the output of the rewinding detection circuit 20 becomes “1” as shown in FIG.
Supplied to 22. Therefore, the reproduction instruction pulse is not generated in the output of the NOR gate 22, the pulse counter 28 does not count the reproduction instruction pulse, and the reproduction instruction pulse is supplied to the VTR 10 through the AND gate 30, the relay contact 35, and the OR gate 36. However, since the VTR 10 cannot reproduce, the reproduction operation is not performed and the generation of the reproduction instruction pulse continues.

Eventually, when the rewinding of the VTR 12 is completed, the output of the rewinding detection circuit 20 becomes “0”, the reproduction instruction pulse is supplied to the clock terminal of the pulse counter 28 via the NOR gate 22, and the pulse counter 28 outputs the reproduction instruction pulse. Start counting. When this count value reaches a predetermined value, the output of the pulse counter 28 becomes "1", a reproduction instruction pulse is generated at the output of the AND gate 32, and the relay contact 40 and the OR gate 38
Is supplied to the VTR 12 via the, and the VTR 12 starts the reproducing operation. Thereafter, the VTR 12 performs the continuous reproduction operation in the same manner. In the above description, the VTR 10 has been described as being inoperable from the beginning due to a failure or the like.However, even if the VTR 12 is inoperable due to a failure or the like while alternately performing the reproducing operation, the VTR 12 is also disabled. Continuous playback operation can be performed.

Although the latch relay is used in the above embodiment, a switching transistor or the like may be used instead of the latch relay, and a tape recorder or the like may be used instead of the VTR.

[Brief description of drawings]

FIG. 1 is a block diagram of one embodiment of a magnetic reproducing apparatus switching circuit according to the present invention, FIG. 2 is a timing chart in the case of the alternate reproducing operation of the same embodiment, and FIG. 3 is one magnetic reproducing of the same embodiment. FIG. 4 is a block diagram of a conventional magnetic reproducing device switching circuit in the case of continuous operation of the device. 10, 12 …… VTR (Magnetic Reproducing Device), 14 …… Switching means, 16
...... Reproduction signal detection circuit, 18 …… Pulse generation circuit, 28 ……
Pulse counter.

Claims (1)

[Claims] 1. A first and second magnetic reproducing device which is in a reproducing state when a reproducing instruction pulse is supplied, and a first magnetic reproducing device which is in a non-reproducing state when both of the first and second magnetic reproducing devices are in a non-reproducing state. And a reproduction signal detecting circuit for generating a reproduction detection signal which is in the second state when one of the first and second magnetic reproduction apparatuses is in the reproduction state, and in response to the reproduction operation of the first magnetic reproduction apparatus. Is switched from the first magnetic reproducing device side to the second magnetic reproducing device side, and in response to the reproducing operation of the second magnetic reproducing device, the second magnetic reproducing device side is switched to the first magnetic reproducing device side. In response to the reproducing operation of the first switching unit and the first magnetic reproducing apparatus, the first magnetic reproducing apparatus is operated by the first magnetic reproducing apparatus.
A second switching unit which is switched to the magnetic reproducing device side of the second magnetic reproducing device and is switched from the first magnetic reproducing device side to the second magnetic reproducing device side in response to the reproducing operation of the second magnetic reproducing device; A pulse generation circuit for starting the generation of the reproduction instruction pulse according to the first state of the above and for stopping the generation of the reproduction instruction pulse according to the second state of the reproduction detection signal,
Rewinding detection When either the first or second magnetic reproducing device is in the rewinding state, the first state is set, and when the first and second magnetic reproducing devices are both in the non-rewinding state, the second state is set. Rewinding detection A rewind detection circuit for generating a signal, and when the replay detection signal is in the first state and the rewind detection signal is in the second state, the replay instruction pulse is counted and the count value becomes a predetermined value. A counter that generates a count signal that becomes a second state when the count value is equal to or more than the predetermined value in the first state, and that supplies the reproduction instruction pulse to the first switching unit when the count signal is in the first state. A switching circuit of a magnetic reproducing apparatus, comprising: 1 gate means and second gate means for supplying the reproduction instruction pulse to the second switching portion when the count signal is in the second state.