JPH0445299Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a waveform shaping circuit that shapes a sine wave signal into a pulse signal.

[Technical background of the invention and its problems] Conventionally, some waveform shaping circuits are configured as shown in FIG. That is, in this waveform shaping circuit, the analog input signal Sin supplied to the input terminal 11 is connected to the input amplitude limiting element (diode).
If the contact potential of CR1 and CR2 is not exceeded, or if the output signal Sout does not exceed the contact potential of feedback amplitude limiting elements (diodes) CR3 and CR4, the amplifier A1 (gain = R2/R1 ) and output from the output terminal 12. On the other hand, when the input signal Sin or the output signal Sout exceeds the contact potential of each of the amplitude limiting elements CR1 to CR4, the corresponding amplitude limiting element becomes energized and limits the amplitude at the contact potential level. For example, the input signal Sin shown by the dotted line in FIG. 4A is amplitude limited by input amplitude limiting elements CR1 and CR2 as shown by the solid line in the figure. Furthermore, as shown by the dotted line in the middle of FIG. 1B, the amplitude of the output signal Sout to be output is limited by the feedback amplitude limiting elements CR3 and CR4 as shown by the solid line in the drawing.

Now, if we consider the case where the input signal Sin has a wide dynamic range, the waveform shaping circuit described above will perform the waveform shaping circuit as shown in Fig. 5b and c for two large and small input signals S1 and S2 shown in Fig. 5a. Output signal S
1' and S2', however, the pulse width of the output signal changes due to changes in the amplitude of the input signal, and the difference in contact potential of the amplitude control element causes vertical imbalance, resulting in an output with a duty of 50%. is not obtained. Furthermore, the output amplitude cannot be made completely constant as shown in FIG. 6 due to variations in the output amplitude due to changes in the input level. Also, if the input level is extremely large, the amplitude suppression effect will be lost, so especially if the input signal has a wide dynamic range, the third
It is necessary to connect the waveform shaping circuits shown in the figure in multiple stages.

Therefore, the conventional waveform shaping circuit as described above has the drawback that the duty of the output signal changes in response to a change in the input level, and furthermore, the output amplitude cannot be made completely constant. In addition, when the dynamic range of the input signal to be handled is considerably wide, it is necessary to connect waveform shaping circuits in multiple stages, resulting in an increase in the scale of the hardware.

[Purpose of the invention] This invention was made to improve the above problems.
% of the output signal.

[Summary of the invention] In other words, the waveform shaping circuit according to this invention generates a trigger pulse when the absolute value of a sine wave signal level exceeds a predetermined value using a pulse generator, and converts this pulse train signal into a trigger pulse using a pulse converter. The pulse train signal is converted into a pulse signal that is inverted every other time, and the converted pulse train signal is amplified or attenuated to a predetermined voltage by a level controller.

[Embodiment of the invention] Hereinafter, an embodiment of the invention will be described in detail with reference to FIGS. 1 and 2.

FIG. 1 shows its configuration, in which the analog input signal Sin is passed through the input terminal 21 to the pulse generator 2.
2. The pulse generator 22 is composed of a differentiating circuit, a voltage comparator, etc., and converts an input signal into a pulse train signal according to its frequency. The output of this pulse former 22 is supplied to a pulse converter 23. This pulse converter 23 is composed of a flip-flop, a counter, etc., and digitally shapes the waveform of the input pulse train signal to convert it into a pulse train signal with a duty of 50%.
The output of this duty shaper 23 is supplied to a level controller 24. This level controller 24 is composed of an amplifier, an attenuator, or the like, and increases or decreases the input pulse train signal to a predetermined amplitude level and outputs it from the output terminal 25.

That is, when this waveform shaping circuit receives an undistorted sine wave signal Sin as shown in FIG. is generated, and a pulse train signal S as shown in FIG.
22 is formed. Then, this pulse train signal S2
2 is supplied to the pulse converter 23 and converted into a pulse train signal S23 in which every other trigger pulse is inverted as shown in c of the figure. This pulse train signal S23
is 50% duty. Furthermore, this pulse train signal S23 is supplied to the level controller 24, and
Or the predetermined level ±V1 or ± as shown in e.
It amplifies or attenuates up to V2, thereby obtaining an amplitude-limited output.

Therefore, the waveform shaping circuit configured as described above converts a sine wave signal into a pulse train signal according to its frequency, and performs digital processing on this pulse train signal to eliminate amplitude changes and dynamics of the input signal. The output amplitude can be safely suppressed with a duty of 50% without being affected by differences in range.

[Effects of the invention] As described above, according to this invention, it is possible to provide a waveform shaping circuit that can obtain an output signal with a constant output amplitude and a duty of 50%.

[Brief explanation of the drawing]

Fig. 1 is a block circuit configuration diagram showing an embodiment of the waveform shaping circuit according to this invention, Fig. 2 is an output waveform diagram of each part to explain the operation of the same embodiment, and Fig. 3 is a conventional waveform shaping circuit. 4 and 5 are output waveform diagrams for explaining the operation of the conventional waveform shaping circuit, and FIG. 6 is a characteristic diagram showing the input/output characteristics of the conventional waveform shaping circuit. It is. 21...Input terminal, 22...Pulse former, 2
3... Pulse converter, 24... Level controller, 2
5...Output terminal.

Claims (1)

[Scope of utility model registration request] A pulse former that generates a trigger pulse when the absolute value of the undistorted sine wave signal level exceeds a predetermined value, and a pulse train signal output from this pulse former is supplied and inverted every other trigger pulse. 1. A waveform shaping circuit comprising: a pulse converter that outputs a pulse signal; and a level controller that amplifies or attenuates the pulse train signal output from the pulse converter to a predetermined voltage.