JPH06300794A - Filtering apparatus - Google Patents

Abstract

PURPOSE:To obtain a stable energy value irrespective of a data position in an input signal. CONSTITUTION:A filter 1 waveform-processes an input signal S0. A data inverter 4 generates a signal having reverse timing order to that of the input signal. A filter 5 waveform-processes an output signal of the inverter 4. A detector 2 detects an output signal obtained by the filter 1. A detector 6 detects an output signal obtained by the filter 5. An energy value calculator 3 calculates a final energy value by using the two energy values obtained by the detectors 2, 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filtering apparatus suitable for performing filtering, that is, waveform processing, on data having a smaller number of continuous data than a delay of a filter such as a television signal.

[0002]

2. Description of the Related Art FIG. 10 shows an example of a conventional filtering device. The filter 101 is, for example, S100.
The input signal, which is the step input, is received and filtered, that is, waveform processed, to obtain a filter output signal as in S101. The detector 102 performs absolute value detection and integration on the output signal of the filter 101, and S10
A detection output such as 2 is obtained and an energy value is output.

Further, in the preceding stage of the conventional filtering device of FIG. 10, a window function such as a Gaussian window is applied to the input signal, the input signal is multiplied by the window function, the input signal, that is, the end of the data is held, and the data is stored. Conventionally, there is one that is appropriately added and filtered.

[0004]

In the above-described conventional filtering device, when an input signal containing a small number of data is filtered, a problem occurs due to the influence of the data position and the influence of the group delay.

First, regarding the influence of the position of data, for example, considering a step waveform as an input signal,
In the step waveform, the data components are concentrated on the rising portion, and as shown in FIG. 11, the filter output is almost converged when the rising data is fast, but as shown in FIG. 12, when the rising is slow, , The filter output is truncated before it converges. For this reason, even if the waveform is exactly the same, the energy value differs depending on the rising position, that is, the data position, and the desired energy value cannot be obtained.

Next, regarding the influence of group delay, for example, IIR (Infinite Impulse Re)
When a steep cutoff characteristic is realized by the (Sponse) filter, the group delay becomes very large. In this case, even when the impulse is located in the middle of the data, the group delay is large, and the filter output is interrupted before it converges, which causes the same problem.

The present invention has been made in view of such a situation, and an object thereof is to provide a filtering device for removing the influence of the position of data such as the rising position and the group delay.

[0008]

SUMMARY OF THE INVENTION A filtering device of the present invention comprises inverting means for inverting the temporal order of an input signal (eg, data inverter 4 of FIG. 1) and waveform processing or filtering of the input signal. 1 filter means (for example, filter 1 in FIG. 1), a second filter means (for example, filter 5 in FIG. 1) for waveform-processing or filtering the data output from the inverting means, and the first filter means. First detection means (for example, the detector 2 in FIG. 1) for detecting the output signal, and second detection means (for example, for the output signal obtained by the second filter means (for example,
Energy detector 6) of FIG. 1 and energy value calculator for calculating a final energy value using the two energy values obtained by the first and second detectors (for example, the energy calculator of FIG. 1). 3) and are provided.

[0009]

In the filtering apparatus of the present invention, the input signal is subjected to waveform processing by the first filter means, and the signal whose time sequence is reversed from that of the input signal is subjected to the waveform processing by the second filter means, and the first filter means performs the waveform processing. The output signal obtained is detected by the first detection means, the output signal obtained by the second filter means is detected by the second detection means, and two energy values obtained by the first and second detection means are used. Then, the final energy value is calculated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of an embodiment of the filtering device of the present invention. Filtering device 1 of this embodiment
0 is a filter 1, a detector 2, an energy value calculator 3,
A data inverter 4, a filter 5 and a detector 6 are provided.

The input signal S0 having a step waveform is sent as it is to the filter 1 via the path A and is sent to the data inverter 4 via the path B. Filter 1 is a normal I
It is configured as a band-pass filter by an IR digital filter, and waveform-processes or filters an input signal and outputs a signal S1. The data inverter 4 outputs a signal S2 in which the temporal order of the input signals is reversed. Like the filter 1, the filter 5 is configured as a bandpass filter by an ordinary IIR digital filter, and waveform-processes or filters the above-mentioned time-inverted signal output from the data inverter 4 to output a signal S3.

The detector 2 detects the output signal obtained by the filter 1, and sums the outputs after the absolute value detection. The detector 6 detects the output signal obtained by the filter 5, and sums the outputs after the absolute value detection. The energy value calculator 3 calculates the final energy value using the two energy values obtained by the detectors 2 and 6.

The data inverter 4 can be composed of a stack memory, for example, as shown in FIG. In the example of FIG. 2, the input data is sequentially stored from the lower address of the stack memory. Then, when the storage of all the data to be processed is completed, the data is sequentially read from the upper address of the stack memory. The input data handled by the present invention is finite, and by using such a stack memory, it is possible to generate a signal whose time sequence is opposite to that of the input signal.

The energy value calculator 3 outputs (1) the sum of the energy values of the detectors 2 and 6, (2) compares the energy values and outputs a large value, and (3) appropriately weights them. Although various configurations such as taking the sum and outputting the same can be adopted, the sum is output here.

In the embodiment of the present invention having the above-mentioned structure,
The data position of the input signal, that is, the significant signal is S0 in FIG.
If the input signal is biased toward the end, as in
Then, the output of the filter 1 is interrupted before it sufficiently converges. However, in the path B, the filter 5 filters a signal whose order is opposite in time to the input signal. The output approaches convergence.
Therefore, when the data in the input signals are the same, the energy values obtained from the calculator 3 are the same even if the data positions are different.

FIG. 3 shows an embodiment of a frequency analysis device including a plurality of the filtering devices of FIG. In FIG. 3, the frequency analysis device 20 includes a plurality of filtering devices 10 having different pass bands, that is, a plurality of band pass filters, and a multi band pass filter.

The output value obtained by filtering the input waveform S10 by the frequency analysis device 20 of FIG. 3 configured as described above is the energy value of each band included in the input signal. When the pass bands of 10 are arranged in this order, the spectrum S11 of the input waveform can be obtained.

By the frequency analysis device 20 described above, FIG.
6 and 7 show a step waveform having a fast rising edge as shown in FIG. 6 and a spectrum obtained by processing a step waveform having a slow rising edge as shown in FIG. 5, respectively. On the other hand, FIGS. 8 and 9 show spectra obtained by processing the step waveforms of FIGS. 4 and 5 by the conventional method.

As is apparent from FIGS. 6 to 9, in the conventional method, the obtained spectrum has a large difference depending on which position of the input signal contains a large amount of data components, that is, significant signal components. By using the present invention, it is possible to reduce the spectrum difference due to the difference in the data position in the input signal. That is, it can be seen that by using the present invention, a more stable spectrum can be obtained regardless of the data position in the signal, as compared with the conventional method.

The present invention is not limited to the above-mentioned embodiment, and is always effective when the energy value is obtained by filtering data having a small number of data.

[0021]

According to the filtering device of the present invention,
A final energy value is calculated by using two energy values obtained by performing waveform processing, that is, filtering the input signal and the signal whose temporal order is opposite to that of the input signal, and detecting the resulting signal. Therefore, it is possible to prevent the energy value from largely different depending on the data position, that is, the position of the significant signal, and also when the filter is an IIR filter, the influence of the group delay can be prevented and stable energy can be obtained. You can get the value.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a filtering device of the present invention.

FIG. 2 is a diagram showing a specific example of a data inverter 4 of the embodiment of FIG.

FIG. 3 is a block diagram showing an embodiment of a frequency analysis device including a plurality of the filtering devices of FIG.

FIG. 4 is a diagram showing an example of a step waveform having a fast rising edge input to the embodiment of FIG.

5 is a diagram showing an example of a step waveform having a slow rising edge, which is input to the embodiment of FIG.

6 is a diagram showing an example of a spectrum obtained by processing a step waveform having a fast rising edge by the frequency conversion device of FIG.

7 is a diagram showing an example of a spectrum obtained by processing a step waveform having a slow rising edge by the frequency conversion device of FIG.

FIG. 8 is a diagram showing an example of a spectrum obtained by processing a step waveform having a fast rise according to a conventional technique.

FIG. 9 is a diagram showing an example of a spectrum obtained by processing a step waveform having a slow rising edge according to a conventional technique.

FIG. 10 is a block diagram showing an example of a conventional filtering device.

11 is a waveform diagram showing a filter output in the case where a step waveform having a fast rising in which data components, that is, significant signal components are concentrated is input to the conventional filtering device of FIG.

12 is a waveform diagram showing a filter output when a step waveform having a slow rising edge in which data components, that is, significant signal components are concentrated is input to the conventional filtering device of FIG.

[Explanation of symbols]

 1,5 Filter 2,6 Detector 3 Energy value calculator 4 Data inverter 10 Filtering device 20 Frequency analysis device

Claims (2)

[Claims] 1. Inversion means for inverting the temporal order of input signals, first filter means for waveform-processing the input signal, and second filter means for waveform-processing the signal output from the inversion means. First detection means for detecting the output signal obtained by the first filter means, second detection means for detecting the output signal obtained by the second filter means, and first detection means for the first and second detection means An energy value calculation means for calculating a final energy value using the obtained two energy values. 2. The first and second filter means are I
The filtering device according to claim 1, wherein the filtering device is an IR filter.