JPH063465Y2 - Input device for signal processor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial application field" The present invention relates to an input device for inputting a signal to be processed to a signal processing device constituted by, for example, a computer.

"Prior Art" FIG. 5 shows a conventional input device for a signal processing device. The processed signal input to the input terminal 1 is adjusted by the preamplifier 2 to have an amplitude value suitable for AD conversion, and the amplitude-adjusted processed signal is input to the AD converter 3.

The AD converter 3 AD-converts the signal to be processed, inputs the digital signal into the signal processing device, and performs processing such as waveform analysis.

However, in such a configuration, only the waveform portion to be input in the signal to be processed is cut out, and the cut-out waveform portion is AD.
It was not possible to convert and input the digital signal to the processing device.

[Problems to be Solved by the Invention] In the variable gain amplifier 2, the amplitude of the processed signal is the AD converter 3
The amplitude value of the signal to be processed is adjusted so as to fall within the amplitude range capable of AD conversion.

However, there are cases where it is desired to magnify only a part of the signal to be processed for waveform analysis.

For example, in the case of a television signal as shown in FIG. 6, even when it is desired to analyze only the portion A, conventionally, the amplitude is adjusted so that the entire amplitude M falls within the allowable amplitude range of the AD converter. A method is adopted in which the entire amplitude M is AD-converted and input to the signal processing device 4, and only the waveform portion A is analyzed inside the signal processing device 4.

In this case, the number of bits for AD-converting the part A is limited to a small number of bits with respect to the total number of bits of the AD converter 3, so that the AD-converted data of the part A has a drawback that the resolution is deteriorated.

An object of the present invention is to propose an input device for a signal processing device, which is capable of AD converting a part of a signal to be processed with high resolution.

"Means for Solving the Problem" In this invention, an offset generator capable of generating an arbitrary DC voltage (or current) and a processed signal in which an alternating current faster than a change in the direct current is superimposed on a stepped direct current An analog adder for adding an offset corresponding to one step of the stepped DC, and an amplitude limiter provided on the output side of the analog adder for cutting out a waveform portion between predetermined first and second levels, An input device for a signal processing device is configured by an amplifier that amplifies a waveform portion cut out by the amplitude limiter and an AD converter that AD-converts the output of the amplifier at a speed higher than the AC current.

According to the structure of the present invention, the center of the desired waveform portion between the predetermined first level and the second level is matched with the center value of the amplitude limiter by adding the offset voltage corresponding to the signal to be processed, and thereby the desired value is obtained. It is possible to cut out a desired waveform portion by removing the portion other than the waveform portion with a limiter.

Therefore, by amplifying and applying this waveform portion to the allowable input amplitude of the AD converter, only this waveform portion can be AD-converted at a higher speed than the above AC using all bits of the AD converter.

Therefore, even a part of the signal whose overall amplitude is large has good resolution A
The signal can be D-converted and input to the signal processing device, and a highly accurate signal processing result can be obtained.

"Embodiment" FIG. 1 shows an embodiment of the present invention. In the figure, 1 is an input terminal for a signal to be processed, 2 is a preamplifier, 3 is an AD converter, and 4 is a signal processing device, which is the same as the conventional one.

In this invention, an analog adder 5, an amplitude limiter 6 and, if necessary, an amplifier 7 for amplitude amplification are provided in front of the AD converter 3, and an offset generator 8 for giving an arbitrary offset to the analog adder 5 is provided. .

The offset generator 8 can generate positive and negative voltages (or currents), for example.

An AD converter can be used, and the offset generated by the offset generator 8 is given to the analog adder 5 and added to the processed signal input from the input terminal 1.

For example, when it is desired to enlarge the waveform portion A shown in FIG. 6 to perform signal processing, a negative offset is applied to the analog adder 5 and the value of this offset is selected so that the center of the waveform portion A is set to the amplitude limiter. Match the center of the limited voltage range.

As a result, only the required waveform portion A can be cut out from the amplitude limiter 6, the cut-out waveform portion A is amplified by the expansion amplifier 7, and its amplitude falls within the allowable input range of the AD converter 3. If it is set to reach the maximum, the number of bits of the AD converter 3 can be used to the maximum extent to perform the AD conversion.

FIG. 2 shows an embodiment of the main part. In this example, the case where the analog addition circuit 5 is provided on the input side of the variable gain amplifier 2 is shown. That is, the offset generator 8 is connected to the input terminal of the operational amplifier forming the preamplifier 2, and analog addition is performed on the input side of the operational amplifier.

The limiter 6 can be configured by a diode anti-parallel connection circuit, and the limit voltage range is ± 0 depending on the conduction voltage of the diode.
A 7V limiter can be obtained.

"Modified Embodiment" FIGS. 3 and 4 show a modified embodiment of the present invention. Third
In the embodiment shown in the figure, the limiter 6B is also provided at the subsequent stage of the expansion amplifier 7.
The case where is provided is shown.

In this way, by providing the limiter 6B also at the subsequent stage of the expansion amplifier 7, the removal rate of unnecessary portions can be increased.

In the embodiment shown in FIG. 4, analog adders 5A and 5B, offset generators 8A and 8B, amplitude limiters 6A and 6B, expansion amplifiers 7A and 7B, and AD converters 3A and 3B are provided on the output side of the preamplifier 2, respectively. The case where two sets are provided and the waveforms of different portions of one signal to be processed are enlarged and AD-converted is shown.

[Advantage of Device] As described above, according to the device, a processed signal in which a direct current faster than the direct current is superimposed on a stepped direct current is input, and a waveform portion in a desired level range is enlarged. AD
The signal can be converted, and the AD-converted digital signal can be input to the signal processing device 4.

Therefore, it is possible to perform highly accurate signal processing even in a small amplitude portion.

Further, since the amplitude limiter 6 removes an unnecessary portion and the amplification amplifier 7 amplifies, the expansion amplifier 7 is not saturated. Therefore, even a relatively high-speed signal can be amplified and AD-converted without distortion.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a connection diagram showing a concrete embodiment of an essential part of the present invention, and FIG.
FIG. 4 and FIG. 4 are block diagrams showing a modified embodiment of the present invention, and FIG. 5 is a block diagram for explaining a conventional technique.
FIG. 6 is a waveform diagram for explaining the inconvenience of the conventional technique. 3: AD converter, 5: analog adder, 6: amplitude limiter, 7: amplification amplifier, 8: offset generator.

Claims (1)

[Scope of utility model registration request] 1. A. An offset generator that generates an arbitrary DC voltage (or current), and B. An analog adder for adding, from the offset generator, an offset corresponding to one stage of the stepped DC to a processed signal in which an AC faster than the change of the DC is superposed on the stepped DC; An amplitude limiter which is provided on the output side of the analog adder and cuts out a waveform portion between predetermined first and second levels; An amplifier that amplifies the waveform portion cut out by this amplitude limiter; An input device for a signal processing device, which comprises an AD converter that performs AD conversion of the output of the amplifier at a speed higher than the AC current.