JPS5827429Y2 - Control signal generation circuit - Google Patents

Description

[Detailed description of the invention] This invention generates a control signal for a period of time until a predetermined number of pulses are applied, and after the predetermined number of pulses are applied, the control signal is interrupted. This invention relates to a type control signal generation circuit.

In tape recorders and the like, a tape counter is commonly used to display the current position.

The simplest tape counter detects the rotation of the reel axis.

The tape counter is incremented according to the rotation of the reel from the start of rotation of the reel, but such a tape counter is used only when driving a tape with a fixed tape length, such as a cassette tape, from the middle. Currently it is not possible to display the absolute position.

Furthermore, by counting the number of reference pulses generated from the reference oscillator during one revolution of the reel shaft, the current absolute position of the tape can be determined, and this counting is performed every time the reel shaft rotates. From this point, it is possible to display the position according to the tape running.

However, in such a way. Sequential display may not be possible due to errors such as uneven rotation of the reel shaft or variations in tape thickness.

It has the disadvantage of giving the user a strange feeling.

Even when driving a tape with a fixed tape length from the middle, first count the current absolute position.

After that, the value of the above-mentioned count is changed according to the running of the tape.The controller displays the position according to the running of the tape (time remaining, number of remaining turns,
To briefly explain this, initial value counting is performed to detect the current absolute position.

For tape G, where the length of the tape is fixed, the thickness of the tape, the diameter of the reel shaft, the running speed, etc. are fixed.

If the rotation period of the reel shaft can be detected, the current absolute position (how many centimeters from the beginning of the tape the current state is) can be calculated.

The rotation period of the reel shaft is one rotation of the reel shaft (
This can be easily detected by counting how many pulses of a constant frequency from the reference oscillator are included (between the pulses generated from the reel axis).

Therefore, after detecting the rotation period of the reel shaft, data such as the rotation period of the reel shaft and the thickness of the tape are inserted into a formula corresponding to one display object, for example, one remaining roll of tape.

You can calculate the number of remaining tape rolls that can be pasted the current position.

This becomes the initial value.

As described above, initial value counting is possible as long as the rotation period of the reel shaft can be detected, so that the initial value counting can be completed within a few pulses from the start of tape running.

Basically, counting is possible as long as there are two pulses, but by repeating the counting of the number of generated pulses, the initial value becomes a more accurate value.

After initial value counting is completed, by subtracting the pulses generated in response to the rotation of the reel shaft from the initial value, the counted value will decrease as the tape runs, and the remaining amount of tape will be displayed on the display device at the moment. The number of turns can be displayed.

If you want to display something else, such as the remaining time on the tape, just change the counting formula.

Therefore, if you use not just a simple tape counter, but a high-grade tape counter that performs calculations using electric circuits as described above, it would be possible to provide reliable display even when the tape is run from any position, but it would be complicated and expensive. Therefore, it is mainly used as a counter for high-end tape recorders.

The present invention relates to a control signal generation circuit used in the above-mentioned high-grade tape counter.
This will be explained with reference to the drawings.

The figure is a block diagram showing an embodiment of the present invention, in which 1 is a quinary counter having an input terminal A and three output terminals B, C, and D; 2 is a 5-ary counter with first and second input terminals 3 and 4; An input prohibition circuit consisting of a first NAND circuit 6 having an input terminal At of the quinary counter 1 and an output terminal 5 connected thereto;
A prohibition signal generation circuit consisting of a second NAND circuit 10 to which is connected.

11 is from a third NAND circuit 16 whose first input terminal 12 is connected to the output terminal 13 of the second NAND circuit 10 and whose second input terminal 14 is connected to the output terminal of the quinary counter 1 via an inverter 15. 1L is a reel pulse generation circuit that generates a reel pulse according to the rotation of the reel.

18 is 1 when taking out the tape cassette from the tape recorder.
This is the eject switch used.

Thus, the output terminal 13 of the second NAND circuit 10 is connected to the first input terminal 3 of the first NAND circuit 6, and the output terminal 25 of the reel pulse generation circuit IT is connected to the first input terminal 3 of the first NAND circuit 6 via the mode switch 19. 2 input terminal 4
The reset terminal R of the quinary counter 1 is connected to the eject switch 18 and also to the power supply 21 via the capacitor 20.

Next, the operation will be explained.

Now, if the mode switch 19 is switched as shown in the figure and the output terminal 18 of the reel pulse generation circuit 1γ is connected to the second input terminal 4 of the first NAND circuit 6, then the power switch 22 is turned on. A reset signal is applied to the reset terminal Rf via the capacitor 20, and the quinary counter enters the reset state.

The quinary counter outputs outputs as shown in Table 1 to the output terminal BC.
and D.

Therefore, when the quinary counter 1 enters the reset state, the output terminals B, C, and D are set to "L".

"L" and "H" signals are generated, and an "H" signal is generated at the output terminal 13 of the prohibition signal generating circuit γ.

Therefore, when the signal HJ is generated at the output terminal 23 of the output circuit 11, the first input terminal 3 of the input inhibit circuit 2 is generated.
The rHJ signal is applied.

In this state, the reel pulse generating circuit 17
When the pulse is applied, the output terminal 5 of the input inhibit circuit 2
An increment signal is applied to the input terminal A of the quinary counter 1, and the signals at the output terminals B, C, and D of the quinary counter 1 become rLj rLJ and rLJ.

Therefore, the rLJ signal is generated at the output terminal 23 of the output circuit 11, and this becomes a control signal for the next stage circuit (not shown).

When the second and third pulses are further applied, the quinary counter 1 increments as shown in the first table, but the output circuit 1
1 output terminal 23tC1 rLJ signal continues to be generated,
The rHJ signal continues to be applied to the first input terminal 31 of the input prohibition circuit 2.

Next, when the fourth pulse is applied, rHJ, rHJ and "L" signals are generated at the output terminals B, C and Df of the quinary counter 1.

Therefore, the output terminal 13f of the prohibition signal generation circuit 1 is "L".
A signal is generated and rHJ is generated from the output terminal 23 of the output circuit 11.
When the signal is generated, an "L" signal is applied to the first input terminal 3 of the input inhibit circuit 2.

Therefore, after the fourth pulse is applied, the input inhibition circuit 2 becomes inhibited, and the reel pulse generation circuit 1775
Even if tres is applied to the input inhibit circuit 2, the quinary counter 1 does not increment.

The output signal of the output terminal 23 of the output circuit 11 remains at rHJ.

As mentioned above, the 5-ary counter 1 advances during the intermittent period when the first four pulses are applied, and the output terminal 23 of the output terminal 11 becomes rLJ.
There are two ways to reset the quinary counter 1, although the signal continues to be generated and the rHJ signal continues to be generated after C6.

In other words, one is intermittent power supply, and when recording or playback of the tape is finished, the power is cut off, and then the power is turned on again, the quinary counter 1 is reset to the reset state shown in Table 1. Become.

The other case is when the reset switch 18 is operated.

When you operate the reset switch 18 and take out the cassette.

A reset signal is applied from the power supply 21 to the reset terminal R+ of the quinary counter 1 through the resistor 24 and the reset switch 18, and the quinary counter 1 is placed in a reset state.

Therefore, if you then load the cassette tape and drive the tape recorder, a reel pulse will be generated and the quinary counter will be 1.
are sequentially stepped to generate a predetermined signal at the output terminal 23 of the output circuit 11.

As explained earlier, the control signal generation circuit shown in the figure is 1
This is effective when applied to a tape recorder, but what kind of control signal is used will be explained below.

The tape counter of a tape recorder must set an initial value and count the current position, and must also increment by one step as the tape runs.

Therefore, two counters must be provided, but if the output signal of the control signal generating circuit according to the present invention is used as a control signal, it is sufficient to use only one counter.

That is, when the tape reel rotates and generates pulses after the power switch is turned on, the control signal generating circuit generates the ft1LJ signal during the first few pulses.

Therefore, the counter enters the first state and performs initial value counting.

After the first few pulses are generated, the control signal generating circuit generates an "H" signal.

Therefore, the counter enters the second state and performs counting according to the tape running.

Therefore, only one counter is sufficient.

As mentioned above, the control signal generation circuit devised is as follows:
It is a counter and input inhibit circuit that can accurately generate an output signal according to the number of input pulses.

This has the advantage that the inhibition signal generation circuit and the output circuit can all be placed in an integrated circuit.

It goes without saying that the control signal generation circuit according to the present invention can be applied not only to tape recorders but also to various devices that require this kind of control signal.

[Brief explanation of drawings]

The figure is a circuit diagram showing one embodiment of a control signal generating circuit according to the present invention. Explanation of main drawing numbers, 1...5-decimal counter, 2...
...Input prohibition circuit, 7...Prohibition signal generation circuit, 11...Output circuit.

Claims (1)

[Scope of utility model registration request] A control signal generation circuit that uses a counter that counts the number of input pulses and is configured to generate an output signal during a period when a predetermined number of input pulses are applied (here, the input terminal to which the input pulse is applied and the an input prohibition circuit having an output terminal connected to a counter; and a prohibition signal generation circuit connected to the output terminal of the counter; when the counter counts a predetermined number of pulses, the prohibition signal generation circuit generates a prohibition signal. 1. A control signal generating circuit according to claim 1, wherein the input inhibiting circuit enters an inhibiting state based on the inhibiting signal 1, thereby preventing pulses exceeding the predetermined number from being applied to the counter.