SU371695A1 - SIGNAL DETECTOR RELATIVE PHASE TELEGRAPHY - Google Patents

Description

one

The invention relates to the field of telegraph communication.

A phase relative telegraphy signal detector is known that contains an input signal time delay element and a low-pass filter that uses the method of multiplying each given premise by its previous one.

However, the known detector is optimal only under conditions of additive interference,

In order to attenuate the effect of multiplicative interference, a divider of the instantaneous voltage values of the input signal and the signal from the output of the time delay element, the output of which is connected to the input of the low-pass filter, is introduced into the proposed detector.

The drawing shows a functional diagram of the proposed detector.

The detector contains an element / time delay of the input signal for the duration of one burst, a divider of 2 instantaneous voltage values and a low-pass filter 3.

The detector works as follows.

Let p-send relative phase telegraphy (OFT) has the form

S, (f) + a), (1)

where Un is the amplitude of the 1st parcel;

(In - the carrier frequency of the parcel; un - the lth binary sign, taking the value of "O or" 1, defining the phase of the / r-th parcel. Its preceding parcel has the form

Sn-i ({) Un-i COS (sh, -f al-iTi), (2)

where flre-i- (p-1) -th binary sign, taking the value O or 1, defining the phase of the (p-1) -th parcel. Then, at the output of the divider in the presence of multiplicative interference, the relation

Sn (t) Nn (About Un cos Ы + а „)

15

 (3)

Sn-i (О „-1 (О {/„ COS НЫ + а, т.)

where Nn (t) is a hindrance, ω, P1 is an extrinsic-th premise; Nn - i (t) - interference, concomitant (n-1) -th

the parcel.

Since the average period of multiplicative noise TN is usually much longer than the duration of the elementary parcels TO (for example, in the HF band G / / Tu Yu-100), we can assume that in the interval of comparison of two parcels with a duration of 2to,

N (f) Nn i (i)

30 U, (t} Un-i (f}.

(4) Reduction factors in expression (4), we get 3 „(t) COS (V + Yn) (О cos (V) Depending on the specific implementation of the transmitted binary signal, there can be four combinations yp and un-i. This gives The following value of the fractional expression (5) is because the cosine functions are reduced: Combination Partial 1 a -1 -1 a a -1 -1 O an-1 O Gn-t 1 When the phases of adjacent parcels are equal, a positive parity or "1 is transmitted, if the phases of adjacent parcels are transmitted to Jt by a negative parcel or "-1. Thus, the proposed detector performs the correct detection OFT signals and at the same time eliminates multiplicative interference, i.e., increases the noise immunity of the receiving device. Object of the invention The relative phase telegraphy signal detector containing an element of the input signal time delay and a low-pass filter, characterized in that divider of the instantaneous voltage values of the input signal and the signal from the output of the time delay element, the output of which is connected to the input of the low-pass filter.