JPS6247013B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an automatic mode determination type switching circuit that can be suitably used when displaying temporally continuous signals and intermittent signals or when controlling the level of these signals. Transmitted in circuits that transmit main signals that handle temporally continuous signals and temporally intermittent signals used in communications, etc., or circuits that transmit sub-signals for monitoring, control, etc. By automatically determining the signal mode, intermittent wave period, etc., the corresponding signal level of the main signal transmission circuit, sub signal transmission circuit, etc. set according to the signal mode, intermittent wave period, etc. is selected and output. The present invention relates to an automatic mode determination type switching circuit.

The usefulness of the automatic mode determination type switching circuit is that since the signal mode being transmitted can be determined based on the output signal of the automatic mode determination circuit, it can be used as various monitoring and control signals.

FIG. 1 shows a conventional example using such a switching circuit. This circuit monitors the output power of an amplifier that transmits both continuous waves and intermittent waves. Although the output power is intermittent during intermittent wave transmission, the peak value of the output power is held in a capacitor and the peak value of the output power of the intermittent wave is always displayed (Fig. 2b). A similar display is also performed for the continuous wave mode (Fig. 2a). This circuit can be used without any problems as long as continuous waves and intermittent waves are not transmitted at the same time, but when both are transmitted at the same time, the output waveform will be as shown in Figure 2c, and when the intermittent wave output is 0, the output will be (perspective section in Figure 2c). To solve this problem, remove amplifier 4 from the circuit shown in Fig. 1 and connect amplifier 3 to
A circuit could be considered in which a diode is inserted between the switch 5 and switch 5, but if a low voltage signal level is input, the diode remains off, so the voltage of the peak value holding capacitor does not change, and the input level It was unable to respond to change.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic mode determination type switching circuit which solves the above-mentioned drawbacks.

In order to achieve the above object, the automatic mode determination type switching circuit according to the present invention includes a first transmission circuit including a first amplifier and a first switch connected in this order, a second amplifier, a second switch, and an input switch. a second transmission circuit which is connected in this order to a third amplifier having a large impedance and a third switch, and a peak value holding capacitor is connected to the third amplifier; and a differentiation circuit which differentiates the input signal; A first multivibrator that turns on the second switch for a time sufficiently shorter than the intermittent pulse width to be inputted by the output of the differentiating circuit, and turns on and off the first and third switches by the output of the differentiating circuit. and a second multivibrator that controls the third switch in a complementary manner and turns on the third switch for a time slightly longer than the intermittent pulse width, and when a temporally continuous signal is input, the first transmission Select the circuit and
The second transmission circuit is selected when the intermittent signal or the superimposed signal of the continuous signal and the intermittent signal is input, and each selected transmission circuit outputs a signal level corresponding to the input signal. It has been done.

According to the above configuration, a signal of a predetermined level can be obtained even when a continuous signal and an intermittent signal are superimposed, and the object of the present invention can be completely achieved.

Hereinafter, the present invention will be explained in more detail with reference to the drawings and the like. FIG. 3 is a circuit diagram showing an embodiment of an automatic mode determination type switching circuit according to the present invention. This embodiment is an example in which the circuit is used as a circuit for displaying the output level of an amplifier or the like.

In the figure, a constant DC voltage is applied to the input terminal 1 in the case of continuous wave mode, and an intermittent DC voltage is applied in the case of intermittent wave mode. When a signal during continuous wave mode transmission is applied, when the voltage rises, the amplifier 10 is operated by the pulse generated by the differentiating circuit 11, and the first and second multivibrators 16 and 17 are operated by this output. , a signal is output from each Q terminal, the second and third switch circuits 12 and 14 are closed circuits, and the signal applied from input terminal 1 is first transmitted to the second transmission path (hereinafter referred to as PATH2).
) is output to output terminal 2. The holding time of the outputs of the first and second multivibrators 16 and 17 can be freely set using external capacitors 19 and 20. This output is inverted when the next pulse is not input within the set time, and is held as is when a pulse is input within the set time, and the set time is reset from the time when a new pulse is input. For continuous wave mode,
As mentioned above, PATH2 first becomes a closed circuit, but since the next pulse does not come within the time set by the external capacitors 20 and 21, the output of the multivibrator 17 is inverted and a signal is output from the Q terminal. The third switch 14 is turned OFF, the first switch 13 is turned ON, and the first transmission circuit (hereinafter referred to as
PATH1) becomes a closed circuit.

Next, a case will be described in which a signal during intermittent wave mode transmission is added. In this case, the signal is the rising edge of the intermittent wave, and the differentiating circuit 11 generates a trigger pulse having the same period as the intermittent wave. External capacitor 1
Reference numeral 9 is set so that the first multivibrator circuit 16 operates only for a sufficiently short time with respect to the pulse width of the intermittent wave, and the external capacitor 2
0 is set so that the second multivibrator circuit 17 operates slightly longer than the period of the intermittent wave.

When the aforementioned trigger pulse occurs, the first and second
The multivibrator circuits 16 and 17 operate and a signal is output from the terminal, and the switches 12 and 14
turns on. Since the output of the first multivibrator 16 is sufficiently short compared to the pulse width, the input from the input terminal 1 is passed through the second amplifier 9 and the second switch 12 to the peak value holding capacitor 18.
It turns off immediately after being charged with a sufficiently short time constant. Furthermore, since the output of the second multivibrator 17 is set to operate for a slightly longer period than the period of the intermittent wave, the third switch 14 is in the ON state, and the peak value holding capacitor 18 is charged. The current voltage is output to output terminal 2. Note that since the input impedance of the third amplifier 15 is very high, the charge in the peak value holding capacitor 18 is hardly discharged, so that a signal with no voltage drop is output. Next, when a trigger pulse is input, the first multivibrator 16 operates as before,
The value of the peak value holding capacitor 18 is reset. At this time, since the second multivibrator 17 is in a state where a signal is being output from its terminal, it is not inverted, and the third switch 14 remains on. In this way, for the intermittent wave mode,
PATH2 becomes a closed circuit.

Next, a case where continuous waves and intermittent waves are transmitted simultaneously will be explained. In this case, when the continuous wave is passed first, the circuit switches from PATH2 to PATH1 as described above. Next, when an intermittent wave is input, the second and third switches 12 and 14 turn on.
PATH2 becomes a closed circuit. The charging voltage of the peak value holding capacitor 18 is the continuous wave mode voltage charged via the second amplifier 9 and the second switch 12 when the first trigger pulse is applied, and the intermittent wave mode voltage. is the sum of the peak voltages of Even if the intermittent wave is turned off in this state, the second switch 12 is set to operate for a sufficiently short time relative to the pulse width of the intermittent wave, so the voltage of the peak value holding capacitor 18 is If the next trigger pulse is input during the operating time of the second multivibrator 17 set by the capacitor 20, the peak voltage value during two-wave transmission will be maintained, and if no trigger pulse is input, the voltage will be continuous. This is the voltage value in wave mode.

As is clear from the above description, the present invention includes a first transmission circuit for outputting a temporally continuous signal and a second transmission circuit for outputting a temporally discontinuous signal. Changes in input level can be coped with by providing a determination circuit that determines the incoming signal mode and selectively controls the first and second transmission circuits, and selecting a transmission circuit for each signal. Therefore, if the switching circuit according to the present invention is used as a circuit for monitoring the output power of an amplifier transmitting both continuous waves and intermittent waves, the original purpose of the switching circuit as a monitoring circuit for the amplifier can be achieved. .

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an example of a conventional level monitoring circuit, FIG. 2 is a waveform diagram showing the relationship between the input and output of the level monitoring circuit shown in FIG. 1, and FIG. 3 is an automatic mode determination type according to the present invention. FIG. 2 is a circuit diagram showing an example of a switching circuit. 1...Input terminal, 2...Output terminal, 3, 4,
7, 10...Amplifier, 6, 18...Peak holding capacitor, 8...First amplifier, 9...Second amplifier, 11...Differential circuit, 12...Second switch, 13... first switch, 14... third switch, 15... third amplifier, 16... first
multivibrator, 17... second multivibrator, 19, 20... external capacitor.

Claims (1)

[Claims] 1 A first transmission circuit including a first amplifier and a first switch connected in this order, a second amplifier, and a second
a second transmission circuit, which is connected in this order to a switch, a third amplifier with a large input impedance, and a third switch, and a peak value holding capacitor is connected to the third amplifier, and a differential circuit that differentiates the input signal. circuit, and the second
a first multivibrator that turns on the switch for a time sufficiently shorter than the intermittent pulse width to be inputted; a second multivibrator that turns on the switch No. 3 for a time slightly longer than the intermittent pulse width, and selects the first transmission circuit when a temporally continuous signal is input; Alternatively, when the superimposed signal of the continuous signal and the intermittent signal is input, the second transmission circuit is selected, and each selected transmission circuit is configured to output a signal level corresponding to the input signal. Automatic mode judgment type switching circuit.