JPS598426A - Detector of abnormal waveform - Google Patents

Abstract

PURPOSE:To detect stably an abnormal waveform with high accuracy, by providing a register detected with an output pulse of an oscillator, taking an exclusive OR signal between the 1st and the 2nd outputs of the register as a preset signal, and counting signals with the output of the oscillator. CONSTITUTION:When an input of a detecting pulse and an output of the oscillator 10 are respectively applied to a data input terminal D and a clock input terminal C of a register 11, Q1, Q2 outputs are given respectively from output terminals Q1, Q2 of the register 11 to exclusive OR circuits 12, 12'. The circuit 12 ORes the detected input waveform and the Q1 output, the circuit 12' ORes the outputs Q1, Q2 of the register 11 and the result is applied respectively to a reset terminal R and a preset terminal PE of a counter 13. Further, the counter 13 receives an output of the oscillator 10 at a terminal CP, and when no signal is applied to the terminals R and PE, pulses are counted. When a signal is applied to the terminal PE, a signal of a set circuit 14 given to the terminal P is preset in the counter 13, and when the content of count overflows, an abnormal waveform signal is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a waveform abnormality detector that detects abnormalities in the output pulse width of equipment that uses pulse width modulated waveforms as output waveforms. Another object of the present invention is to provide a detector that can detect the present invention quickly.

In recent years, the number of devices that output pulse-width modulated output waveforms is increasing, and there is a growing need for highly accurate and highly stable waveform abnormality detectors.

Figure 1 is a diagram showing the configuration of a conventional waveform abnormality detector.
The figure is an operation waveform diagram for explaining the operation of each part in Figure 1. In Figure 0, 1 is an integrator, 2 is a pulse edge detector,
3. 3' is a comparator, 4' and 4' are setters, and 5 is an OR circuit (OR circuit), and each part (a) to f shown in Figure 1
The operating state of the PJ is shown corresponding to FIGS. 2(A) to 2(A). As shown in the configuration diagram in Figure 1 and the operating waveform diagram in Figure 2, the conventional detection method is to provide an integrator l that receives the detection pulse shown in Figure 2 (A) as an input, and to Starts the integral operation and pulse edge detector 2
The edge of the detection pulse as shown in Fig. 2 (wing) is detected, and the edge of the detection pulse is given to the comparators 3 and 3' as a comparison command using the detection signal, and the operation of the integrator 1 is stopped and reset. A method has been proposed that prepares for detection pulses.

The operation of this method is shown in Figure 2), where the output of the integrator l is
A comparator 3.3' compares the output signal at the time when the output signal of the pulse edge detector 2 shown in FIG. 2(e) is generated.

If the width of the detection input shown in Fig. 2 (a) becomes longer, the output waveform of the integrator 1 shown in Fig. 2 (a) will become as shown by the dashed-dotted line, and 1), (to) and (
As shown in (g), the pulse edge detector 2, comparator 3, and OR circuit 5 operate (point A). Conversely, Figure 2 (a)
If the width of the detection input shown in Fig. 2 becomes shorter)
The output waveform of the integrator 1 shown in FIG. 2 becomes as shown by the broken line, and as shown in FIG. Circuit 5 operates (point B).

In this way, the abnormality detection signal is extracted from the OR circuit 5 regardless of whether the width of the detection input shown in FIG. 2(A) becomes longer or shorter.

This type of waveform abnormality detection cannot detect missing pulses, and since analog elements such as an integrating circuit are used in the detection circuit, there is an unavoidable drop in accuracy due to temperature drift, etc., and delicate adjustments are required. Become.

Another problem is that the higher the frequency of the detection pulse, the higher the performance of the integrator must be used, and the detector lacks accuracy and stability.

In view of these drawbacks, the present invention has been made to eliminate these problems and enable highly accurate and stable waveform abnormality detection.

Hereinafter, the present invention will be explained based on the drawings of the embodiments. Third
The figure shows the basic configuration of the present invention, where lO is an oscillator that oscillates at a predetermined frequency, 11 is a register that records a detection signal with the output pulse of the oscillator lO, and 12 and 12' are exclusive ORs. Circuit (BX-OR circuit) 13 is a counter, 1
4 is a setting circuit. In the figure, the detected signal is applied to register 11 along with the output pulse from oscillator IO. One output of the register 11 (Qs small output is added to the exclusive OR circuit 12 together with the detected signal. The Q! output of this register 11 is the output of the other register 11 (
Q! output) and is added to the exclusive OR circuit 12'. The counter 13 is a counter that uses the output signal from the oscillator 1O as a clock pulse, and is connected to the exclusive OR circuit 12.
and 12' are applied as reset and preset signals to the counter 13, respectively, and the counter operates such that the value of the setting circuit 14 is preset by the signal from the exclusive OR circuit 12'.

The detailed operation of the above basic configuration will be explained using the configuration diagram in FIG. 3 and the operation waveform diagrams in FIGS. 4 and 5. 4 and 5 are operation waveform diagrams for explaining the operation of each part in FIG. 3, and each part (A) to (E) and (
The operating states of (g) and (g) are shown corresponding to FIGS. 4 and 5 (a) to (e) and (g).

First, let's explain by referring to Figures 3 and 4. Figure 4 (a)
The input of the detection pulse shown in FIG. 4 and the output of the oscillator lO shown in FIG.
When it is added as an input to the register 11, the Q1 output shown in FIG.
Therefore, the Q2 outputs each have a waveform delayed by the output cycle of the oscillator 10 from the Q1 output shown in FIG. 4(C). The exclusive OR circuit 12 calculates the logic between the detected input waveform (FIG. 4 (a)) and the Q1 output of the register 11, and the exclusive OR circuit 12' calculates the logic between the Q1 output of the register 11 and Q! The logic of the output is taken, and a reset signal (fourth
)) and a preset signal (FIG. 4(e)).

The counter 13 counts the pulses input to the terminal cp when no signal is applied to its reset terminal ⇒ and preset terminal PR. Also, when a signal is applied to the reset terminal, the count value becomes zero unconditionally.
When a signal is applied to the preset terminal PB, the signal from the setting circuit 14 applied to the terminal P is unconditionally preset in the counter 13. The output terminal CO of the counter 13 outputs a signal (waveform abnormality signal) when the count contents overflow/<-flow, and in the case of an N-bit counter, it outputs an output signal when two pulses are counted. FIG. 4(f) shows the operating state of the count amount of the counter 13.

Therefore, the frequency of the detection input is the frequency of the F1 oscillator IO! , the number of bits of the counter 13 is N1, the number of presets by the setting circuit 14 is n1, and the number of pulses of the oscillator IO which is equivalent to the pulse width for abnormality detection is n'.

Here, if the detected pulse waveform is normal, or if the change is within the range of the value set by the setting circuit 14, the counter 13 will not overflow, and therefore no signal (abnormal waveform signal) will be output from the CO terminal.

Figure 5 shows the operating status of each part when the detection input changes more than the value set by the setting circuit 14 ((a) to ()).
The small CO output of the counter 13 at this time (FIG. 5(g)) may be used as the abnormality detection signal.

According to this method, it is possible to detect abnormalities including pulse waveform dropouts with a very simple circuit configuration, and since the detection is performed in a digital manner compared to the conventional method, its accuracy and stability are significantly improved.

FIG. 6 is a block diagram showing another embodiment of the present invention.
Items with the same numbers as in the figure indicate items having the same functions. In the configuration diagram of FIG. 6, the register 11 is provided with another output terminal Q3 in addition to the output terminals Qs and Q, although the explanation that overlaps with FIG. 3 will be omitted. In addition to the exclusive OR circuit 12゜12', an exclusive OR circuit 1r is also provided, and the register 11
The Q2 output and Q3 output of are added to the exclusive OR circuit 12'. 15 is a setting circuit, 16 is a digital comparator, and 17 is a logic circuit (OR circuit). The output of the exclusive OR circuit 12 in FIG. A reset signal and a preset signal are applied to terminal PE.

The operation waveform diagram shows the operation status of each part (A) to ■ shown in Figure 6 (
9) The states are shown in FIGS. 7 (A) to (M) and FIG. 8 (A) to Saki. The explanation will be omitted. Fig. 8 shows the operating state when the detection input changes more than the value set by the setting circuit, and the exclusive OR circuit 1 shown in Fig. 8 (v)
Since the digital comparator 16 performs a comparison operation only when the output of the counter 2 is given as a comparison command signal to the digital comparator 16, at this time, the output of the counter 13
If the value of the count output Qs-Qn is smaller than the digital amount given by the setting circuit 15, the digital comparator 16 will output an abnormality detection signal as shown in FIG. The OR circuit 17 in FIG. 6 is shown in FIG.
The CO small output of the counter 13 by the operation explained in FIG. 5 is logically summed with the output of the digital comparator 16, and an abnormality detection signal is output as the output.

As described above, according to the present invention, it is possible to detect not only a missing pulse in a pulse train but also an abnormality in the pulse waveform with high precision and high stability.

It is possible to realize a very good detector, and its range of applications is wide, such as monitoring reference signal waveforms and detecting abnormalities in pulse width control equipment, and its industrial value is extremely high.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a conventional waveform abnormality detector, Fig. 2 is a diagram showing operation waveforms of each part of Fig. 1, Fig. 3 is a block diagram showing an embodiment of the present invention, Figs. 4 and 5. are operation waveform diagrams of each part in FIG. 3, FIG. 6 is a configuration diagram showing another embodiment of the present invention, and FIG.
FIG. 8 is an operational waveform diagram of each part of FIG. 6. 1...Integrator %2...Pulse edge detection e, 3゜3'...Comparator, 4.4'...
・Setting device, 5, 17...Order circuit, 10・
...Oscillator, 11...Register, t2
, 12'. 12'...Exclusive OR circuit, 13...
・Counter, 14゜15...Setting circuit, 16・
...Digital comparator. Patent applicant Toyo Denki Seizo Co., Ltd. Representative Atsushi Doi

Claims (1)

[Claims] 1. A waveform abnormality detector for detecting an abnormality in the output pulse width of a device whose output waveform is a pulse width modulated waveform, comprising: an oscillator that oscillates at a predetermined frequency; and an output pulse of the oscillator. A register for recording the detection signal and a first nuclear register.
An exclusive OR signal of a predetermined output of the register and the detection signal is used as a reset signal, and an exclusive OR signal of the first predetermined output and the second predetermined output of the register is used as a preset signal, and the output of the oscillator is The counter includes a counter that performs counting operation based on pulses, and responds to a value preset by the output of the first setting circuit, and extracts an output signal from a predetermined output terminal of the counter as an abnormality detection signal when a pulse is missing or a waveform is abnormal. A waveform anomaly detector characterized by comprising: 2. A waveform abnormality detector that detects an abnormality in the output pulse width of a device whose output waveform is a pulse width modulation waveform includes an oscillator that oscillates at a predetermined frequency, and a register that records a detection signal using the output pulse of the oscillator. , an exclusive OR signal of the first predetermined output and the second predetermined output of the register as a reset signal, and an exclusive OR signal of the second predetermined output and the third predetermined output of the register. A counter is provided which operates as a preset signal and counts with the output pulse of the oscillator, and the exclusive OR signal of the first predetermined output of the register and the detection signal is used as the second setting circuit output and the count of the counter is provided. A waveform abnormality detector characterized in that the contents are compared, a detection operation is performed when the frequency of the detection input waveform becomes high, and a logical sum with a predetermined output signal of the counter is extracted as an abnormality detection signal.