JPH08237696A - Dial pulse detector - Google Patents

Abstract

(57) [Abstract] [Purpose] A digital dial pulse detector can reduce the signal processing scale and can accurately detect a dial pulse. [Structure] With respect to the input sampling data, the absolute value calculating unit 1 calculates the absolute value of the amplitude, and the smoothing unit 2 calculates a moving average and smooths it. The average value calculating means 3 and the peak value calculating means 4 output the average value and the peak value of the smoothing means 2 at regular time intervals. The outputs of the average value calculating means 3 and the peak value calculating means 4 are compared with the threshold value in the level judging means 5, respectively, to judge the presence or absence of a make pulse or break pulse, and notify the signal judging means 6 of the judgment result. . The signal determining means 6 detects the dial pulse by counting the number of make pulses or break pulses and the time interval between the pulses.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dial pulse detecting device for use in a wired communication system, for example, a digital exchange (PBX) or the like, for detecting an input dial pulse by digital processing.

[0002]

2. Description of the Related Art Conventionally, a dial pulse detecting device by digital processing detects a make pulse and a break pulse generated from a received signal by a transition between a make state and a break state of the dial pulse, and detects the make pulse and the break pulse. Depending on the number, the dial was recognized. In order to prevent erroneous detection of dial pulses due to spike noise, for example, the characteristics of the make pulse and break pulse are recognized, and the following dial pulses are detected by utilizing the characteristics.

[0003]

However, in the above-mentioned conventional digital type dial pulse detecting device, if a simple method is used, there is a possibility of erroneous detection of dial pulse due to spike noise or the like, and in order to prevent erroneous detection. Has a problem that the signal processing scale increases.

The present invention is intended to solve such a conventional problem, and is capable of reducing the signal processing scale and accurately detecting the dial pulse. The purpose is to provide a device.

[0005]

In order to achieve the above object, the present invention provides an absolute value calculating means for calculating the absolute value of the amplitude of an input signal from a sampled line, and an output of the absolute value calculating means. Smoothing means for smoothing, an average value calculating means for calculating an average value of the output of the smoothing means, a peak value calculating means for calculating a peak value of the output of the smoothing means, and an average value calculating means. And level determination means for performing level determination on the output of the peak value calculation means, and the dial pulse is determined from the output of this level determination means,
And a signal determining means for outputting the determination result signal.

[0006]

According to the present invention, after the absolute value of the amplitude of the input signal is smoothed by the above-mentioned structure, the average value and the peak value of the smoothed output are calculated, and the respective levels are judged. Therefore, the dial pulse can be detected without being affected by low-level stationary noise and instantaneous spike noise.

[0007]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a dial pulse detecting device according to an embodiment of the present invention.

In FIG. 1, 1 is an absolute value calculating means for calculating the absolute value of the amplitude of a sampled input signal, and 2 is a constant sample of the output of the absolute value calculating means 1 (for example, 1
A smoothing means 3 for calculating and smoothing a moving average of every 6 samples) and a smoothing means 3 for every fixed time of the output of the smoothing means 2 (for example,
An average value calculating means for calculating an average value for each 2 mS) and 4 are peak value calculating means for calculating a peak value of the output of the smoothing means 2 within a fixed time (for example, 2 mS). Reference numeral 5 is a level determining means for comparing the outputs of the average value calculating means 3 and the peak value calculating means 4 with threshold values, and 6 is a signal determining means for detecting the dial from the result of the level determining means 5.

The operation of the above arrangement will be described below. The absolute value calculation means 1 outputs the absolute value of the amplitude of the sampling data input at the rate of 8 kHz. The smoothing means 2 outputs a moving average for 16 samples every time one sampling data is input, and smoothes the output of the absolute value calculating means 1. The average value calculation means 3 is a smoothing means 2 that is output for each sample input.
The average value of every 2 mS of the output of is output once every 2 mS. The peak value calculation means 4 outputs the peak value of the output of the smoothing means 2 once every 2 mS within the same time as the time (2 mS) which is the target of calculation by the average value calculation means 3. The level determination means 5 compares each output with the threshold value each time there is an output from the average value calculation means 3 and the peak value calculation means 4, and if both values exceed the threshold value, the output is calculated. It is assumed that there is a make pulse or a break pulse within the time of, and the result is notified to the signal judging means 6. The signal judging means 6 detects the dial pulse by counting the number of make pulses or break pulses and the time interval between the pulses from the output of the level judging means 5.

[0011]

As described above, according to the present invention, after the absolute value of the input signal is smoothed, both the average value and the peak value of the smoothed output are level-determined. It becomes possible to detect the dial pulse,
Further, it is possible to realize a dial pulse detection device having a simple configuration and a small signal processing scale.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a dial pulse detection device according to an embodiment of the present invention.

[Explanation of symbols]

 1 Absolute value calculating means 2 Smoothing means 3 Average value calculating means 4 Peak value calculating means 5 Level judging means 6 Signal judging means

Claims (1)

[Claims] 1. An absolute value calculating means for calculating an absolute value of an amplitude of an input signal from a sampled line, a smoothing means for smoothing an output of the absolute value calculating means, and an output of the smoothing means. Average value calculating means for calculating an average value, peak value calculating means for calculating a peak value of the output of the smoothing means, and level determination for performing level determination on the outputs of the average value calculating means and the peak value calculating means Means and the dial pulse from the output of this level determination means,
A dial pulse detection device comprising: a signal determination unit that outputs the determination result signal.