SU853801A1 - Voice-frequency signal identifying device - Google Patents

Description

(54) METHOD OF RECOGNITION OF TONE SIGNALS

one

The invention relates to communication technology and can be used in data transmission systems when building digital information receivers and computer equipment with a communication channel.

One of the known methods for recognizing tonal signals uses a pulse spacing selector that contains an anti-coincidence circuit, front and rear edges for the input pulse, a waiting multivibrator, and a delay line 11.

However, with this method, high frequency interference occurs.

Closest to the proposed method for recognizing tonal signals, including comparing the parameters of received tones with a reference signal and generating a reception signal according to their C 2 coincidence.

However, the known method does not have sufficient noise immunity.

The purpose of the invention is to improve noise immunity.

For this, when recognizing tones before comparing the received and reference signals

the delay of the received tone is made for a time multiple of its period, and the subsequent comparison of the delayed and received tones, whereby the comparison of the received and reference signals is made when the delayed and received parameters coincide.

ten

The proposed method for recognizing tones is as follows.

When recognizing tones, including operations

15 parameters are received} of tonal signals with their reference (permissible) values and generation of a recognition signal based on their deviation, delayed read operations are performed

20 tones for a time multiple of their follow-up period, and a comparison of the parameters of the delayed tone with subsequent signals read from the same line. Production

The recognition signal 25 is also performed under the condition of equality to the parameter delayed and subsequent (subsequent) tones.

Introduction of read tone delay operations and comparison

thirty

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tonal signals to their equalization, about tl and h a y i and with IS

Inner tone with: the purpose of increasing the noise of the KOTOOL package, for a period of accuracy, before comparing, the reception of which there is no interference. For this reason and reference signals, the recognition of tonal signals in 5d TC is the delay of the received on-line with non-stationary pulsed signal for a time multiple of

Interference or packet interference with the use-period, and subsequent comparison.

The purpose of the present invention will be the delayed and received tonal. It is performed with the same accuracy as other signals, and the comparison of receiving lines without interference, which is the received and the reference signals, increases the noise immunity.

delayed and received signals.

Claims (2)

The invention claims are taken into account in the examination Recognition method tones number 479240, cl. H 03 K 5/20, 1974 signals, including a comparison of para-. 2. USSR author's certificate meters received tone-no. 545082, cl. H 04 Q 3/14, 1977. Information sources. 15 1- USSR author's certificate