JPS62145912A - Pulse generating circuit - Google Patents

Abstract

PURPOSE:To generate a pulse with an optional position and width while inputting a single pulse is inputted by constituting the titled circuit by a series circuit comprising the 1st and 2nd monostable multivibrators each having a prescribed time constant. CONSTITUTION:A monostable multivibrator (MMV) 1 is discharged at a time constant tau1 and restored at a time t1 shown in figure (b). On the other hand, a multivibrator MMV 2 starts discharging at a time constant tau2 by using a leading an output of the vibrator MMV 1 at the time t1 as a trigger and is restored at a time t2 as shown in figure (c). Thus, a pulse as shown in figure (d) is obtained. The time t1 is adjusted by changing the time constant tau1, that is, a product between a capacitance C1 of a capacitor 11 and a resistor R1 of a resistor 12. Further, the time t2 is adjusted similarly by changing a capacitor C2 of a capacitor 21 and a resistance R2 of a resistor 22.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pulse generation circuit used, for example, when generating a pulse for sampling a phase error voltage from a sync pulse.

[Conventional technology]

Conventionally, this type of sampling method, as shown in Figure 3, uses a sync pulse as shown in (a) of the same figure.
The burst gate pulse as shown in the figure (b) is
As shown in Fig. 4(b), there is a method of sampling the phase error voltage as shown in Fig. 4(c) by directly using it as a sampling pulse as shown in Fig.
There is a method in which the rising edge of the burst gate pulse shown in FIG.

[Problem that the invention seeks to solve]

However, in the first conventional technology mentioned above, ■ @ Figure 3 (C)
As shown in figure (d), the trailing edge of the phase error voltage is sampled, making accurate sampling impossible. As shown in Figure (c), v fluctuates from 0 to vSl or vS2, making accurate sampling impossible;
This method has drawbacks such as the possibility of sampling errors due to noise before the burst.

Further, in the second prior art, although the above-mentioned drawbacks (1) and (2) have been solved, the drawback (2) still remains as shown in FIG. 4(C). That is, there is a possibility that % MSN may be sampled with respect to the voltage vS that is truly desired to be sampled.

The present invention was made to solve this problem, and an object of the present invention is to provide a pulse generation circuit that can generate a pulse from a sync pulse by freely setting the generation position and width.

[Means for solving problems]

The present invention provides a first monostaple multivibrator having a charging/discharging circuit with a time constant of τI =C,R1 and a second monostaple multivibrator having a charging/discharging circuit with a time constant of τI =C,R. This is a series circuit of staple multi-vibrators.

[For production]

The generation position and width of the sampling pulse are independently determined by the time constants of the charging and discharging circuits of both multivibrators.

〔Example〕

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

In the figure, 1 is the monostaple multi-pipe rake of river 1, and the first capacitor 11 (capacitance value Ct
) and a first resistor 12 (resistance value R+), the circuit has a discharge time constant of τt =C,R. 2 is a second mono-staple multi-vibrator connected in series to the first mono-staple multi-pipe rake 1, a second capacitor 21 (capacitance value C1) and a second resistor 22 (resistance The circuit has a discharge time constant of τ2 =C2R, which has a value R2).

Next, the operation of this embodiment will be explained using FIG. 2.

Triggered by the fall of the input sync pulse a as shown in FIG. 2(a), in the first monostaple multi-vibrator 1, τl = (:, R
Discharge begins with a time constant of 1, and the threshold voltage V
At time t determined by thl, this first monostaple multi-pipe rake 1 returns.

Ten Thousand, Second Monostaple Multi-Vibrator 2
is the first monostaple multiple at time t,
Trigger the rise of the output of vibrator 1 (Fig. 2G)
As shown in FIG. 2, discharge starts with a time constant of τzzctRt.

As a result, as shown in FIG. 2(d), the sampling pulse remains on as the output of the two monostaple multi-pipe rakes 1 and 2 from time t1 until time t when the threshold voltage V th 2 is determined. is obtained.

Here, the time t can be adjusted by changing the discharge time constant τ in relation to the threshold voltage Vtht, that is, by completely changing the capacitance value C3 of the capacitor 11 and the resistance value R1 of the resistor 12. , this t,
By adjusting , it is possible to avoid sampling the error voltage due to the noise before the burst in the phase error voltage waveform as shown in FIG. 2(e).

Also, time 1. By changing the discharge time constant τ in relation to the threshold voltage Vth2, that is, the capacitance value C2 of the capacitor 21 and the resistance value R1 of the resistor 22
By adjusting t2, it is possible to accurately sample the 7Aze error voltage without applying it to the trailing edge (sampling voltage Vs).

Although the sampling pulse for phase error voltage sampling has been described above, the present invention is applicable not only to sampling but also to all cases where the generation position and width need to be determined arbitrarily.

〔Effect of the invention〕

As explained above, in the present invention, τ1=C, R
,, τ2 ” Since it is constructed with a series circuit of monostaple multi-pipelake of 1st and Can generate pulses.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a waveform diagram for explaining its operation, and FIGS. 3 and 4 are diagrams for explaining the conventional sampling pulse generation method. FIG. 1.2...φ Monostable multi pie break, 11,21...Capacitor, 12.22...
·Resistor. Figure 2 t, t2 Figure 3 (d)

Claims (1)

[Claims] It consists of a series circuit of first and second monostaple multi-vibrators with a sink pulse as a trigger input, and the first mono-staple multi-vibrator consists of a first capacitor and a first resistor. C
_1R_1 (C_1 is the capacitance value of the first capacitor, R_1
The second monostaple multi-vibrator includes a charging/discharging circuit having a time constant of τ (resistance value of the second resistor), and the second monostaple multi-vibrator includes a second capacitor and a second resistor.
A pulse generating circuit comprising a charging/discharging circuit having a time constant of 2=C_2R_2 (C_2 is a capacitance value of a second capacitor, R_2 is a resistance value of a second resistor).