RU2234198C1 - Device for receiving minimal angular modulation signals - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: proposed device has synchronizer, first and second correlators, first and second retrieval/storage units, subtraction unit, adder, switching unit, comparator, and relative decoder.

EFFECT: enhanced reliability of signal reception.

1 cl, 5 dwg

Description

The invention relates to telecommunications, namely to digital radio communications, and can be used in signal transmission systems with minimal angular modulation without phase disruption.

A device for receiving frequency-manipulated signals (Fink L. M. Theory of transmission of discrete messages. - M .: Sov. Radio, 1970, p. 155-156), containing a synchronizer, the first and second correlators, the first and second blocks of the calculation module signal, subtraction unit, comparator, the clock input of which is connected to the clock output of the synchronizer and to the clock inputs of the first and second correlators, the information inputs of which are connected to the input of the device, and the reference inputs, respectively, with the first and second reference outputs of the synchronizer, when The trigger output is the device output.

A disadvantage of the known device for receiving frequency-manipulated signals is the lack of fidelity of demodulated signals, because when receiving, the correlation between the symbols of the received signals with minimal frequency manipulation without phase disruption is not taken into account. In addition, the known device does not allow demodulation of signals with minimal phase modulation.

Closest to the proposed is a device for receiving frequency-manipulated signals (ed. St. USSR No. 801298, class N 04 L 27/14, 1981), containing a synchronizer, the first and second correlators, the information inputs of which are connected to the input of the device, the adder , a subtraction unit, a comparator and a relative decoder, the clock input of which is connected to the first clock output of the synchronizer. The known device also contains the first and second blocks of the calculation of the signal module, an additional comparator, two triggers and a first adder modulo two, while the relative decoder is made in the form of a delay element and a second adder modulo two.

The known device provides higher fidelity when receiving signals with minimal frequency manipulation without phase disruption by taking into account the correlation between their symbols.

However, a disadvantage of the known device for receiving frequency-manipulated signals is also the lack of fidelity of demodulated signals, because optimal coherent signal reception with minimal frequency manipulation without phase discontinuity is not realized. In addition, the known device also does not allow demodulating signals with minimal phase modulation.

To eliminate these drawbacks, it is necessary to ensure optimal coherent reception of signals with minimal angular modulation (signals with minimal phase modulation and signals with minimal frequency manipulation).

The objective of the invention is to increase fidelity when receiving signals with minimal angular modulation.

The problem is achieved by the fact that in the device for receiving signals with minimal angular modulation, containing a synchronizer, the first and second correlators, the information inputs of which are connected to the device input, an adder, a subtraction unit, a comparator and a relative decoder, the clock input of which is connected to the first clock synchronizer output, the first and second sampling / storage devices and a switch are introduced, the output of which is connected to the direct input of the comparator, whose inverse input is connected to the zero bus, and the output is the first information output of the device and connected to the information input of the relative decoder, the output of which is the second information output of the device, the clock output of which is connected to the first clock output of the synchronizer, the input of which is connected to the input of the device, the first and second reference outputs respectively to the first and second inputs the adder and the subtraction unit, the outputs of which are connected respectively to the reference inputs of the second and first correlators, the outputs of which are connected to the information input I will give, respectively, the second and first sampling / storage devices, the outputs of which are connected respectively to the second and first information inputs of the switch, the first and second control inputs of which are connected to the control inputs of the first and second sampling / storage devices, to the clock inputs of the first and second correlators, respectively, and respectively, to the second and third clock outputs of the synchronizer.

The proposed device for receiving signals with minimal angular modulation implements optimal correlation reception of signals with both minimal phase modulation and minimal frequency manipulation, which ensures increased fidelity when receiving signals with minimal angular modulation.

A comparative analysis with the prototype showed that the proposed device for receiving signals with minimal angular modulation includes new significant features set forth in the claims. Therefore, the technical solution meets the criterion of "novelty."

Since the required technical result is achieved by the entire newly introduced set of essential features that are not found in the well-known patent and scientific literature at the filing date, the technical solution meets the criterion of "inventive step".

Figure 1 shows the electrical block diagram of the proposed device for receiving signals with minimal angular modulation, figure 2 is a timing diagram explaining its operation, figure 3 is a trellis diagram of the received signals with minimal phase modulation and signals with minimal frequency shift keying two symbolic intervals, figure 4 is an electrical block diagram of a possible embodiment of synchronizer 1, and figure 5 is an electrical block diagram of a prototype.

A device for receiving signals with minimal angular modulation (see Fig. 1) contains a synchronizer 1, first and second correlators 2 and 3, first and second sampling / storage devices 4 and 5, a subtraction unit 6, an adder 7, a switch 8, a comparator 9 and relative decoder 10.

The inputs of the synchronizer 1, the first and second correlators 2 and 3 are connected to the input of the device.

The first clock output of the synchronizer 1 is connected to the clock input of the relative decoder 10 and to the clock output of the device. The second clock output of the synchronizer 1 is connected to the clock input of the first correlator 2, to the control input of the first sampling / storage device 4 and to the first control input of the switch 8. The third clock output of the synchronizer 1 is connected to the clock input of the second correlator 3, to the control input of the second sample device 5 / storage and to the second control input of the switch 8. The first and second reference outputs of the synchronizer 1 are connected to the corresponding inputs of the subtraction unit 6 and the adder 7. The outputs of the subtraction unit 6 and the adder 7 p are connected to the reference inputs of the first and second correlators 2 and 3, respectively. The outputs of the first and second correlators 2 and 3 are connected to the information inputs of the first and second sampling / storage devices 4 and 5, the outputs of which are connected to the first and second information inputs of the switch 8, respectively. The output of the switch 8 is connected to the input of the comparator 9. The first information output of the proposed device is the output of the comparator 9, which is connected to the information input of the relative decoder 10. The second information The output of the proposed device is the output of the relative decoder 10.

A device for receiving signals with minimal angular modulation as follows.

The received signal from the MUM, information in which can be incorporated both in phase - minimum phase modulation (MFM), and frequency - minimum frequency modulation (MFM) in the absence of noise at any symbol interval can be represented by one of four elementary signals defined on the duration of the T symbol as

- амплитуда и начальная фаза сигнала на границе k символа; ω₁ и ω₂ - круговые частоты элементарных сигналов.where a and

- the amplitude and initial phase of the signal at the boundary of the symbol k; ω ₁ and ω ₂ are the circular frequencies of elementary signals.

Any two consecutive symbols with MUM are correlated with each other, which reflect trellis diagrams of signals with MFM and MFM, shown in figure 3, a and figure 3, b.

несущего колебания и принимаемого сигнала с МУМ на границах символьных интервалов, а ребрам - элементарные сигналы, передаваемые в соответствующих символьных интервалах. При этом ребра, показанные пунктирными линиями, соответствуют передаваемым символам "1", а ребра, показанные сплошными линиями, - передаваемым символам "0".The nodes of these trellis diagrams correspond to the phase difference

the carrier oscillation and the received signal with the MUM at the boundaries of symbolic intervals, and edges - elementary signals transmitted in the corresponding symbolic intervals. In this case, the edges shown by dashed lines correspond to the transmitted symbols “1”, and the edges shown by solid lines correspond to the transmitted symbols “0”.

а передаче символа "0" – состояние

При этом, как показано на фиг.3,б, для сигнала с МЧМ передаче символа "0" соответствует сохранение состояния

или

а передаче символов "1" - переход из одного из этих состояний в другое состояние.As shown in figure 3, a, for the signal with the MFM symbol transmission "1" always corresponds to the state

while transmitting the character "0" - state

In this case, as shown in Fig. 3, b, for the signal with the MFM transmission of the symbol "0" corresponds to the preservation of the state

or

and the transmission of characters "1" - the transition from one of these states to another state.

Therefore, the symbols of the signal with the MFM are encoded with a relative code compared to the symbols of the signal with the MFM.

The allowed sequences of elementary signals of the signal with the MUM on a two-character interval are determined by the allowed paths on the trellis diagram.

The allowed sequences of elementary signals of the signal with the MPM (see figure 3, a) when transmitting on the k-character interval of the character "1"

S ₁ , S ₁ or S ₁ , S ₂ ;

S ₃ , S ₁ or S ₃ , S ₂ ,

and when transmitting the character "0" on the k-character interval

S ₂ , S ₄ or S ₂ , S ₃ ;

S ₄ , S ₄ or S ₄ , S ₃ .

Therefore, the decision on the value of the signal received at the k-symbol interval of the symbol with the MFM should be made by sequentially comparing alternative hypotheses about the reception of the allowed sequences of two elementary signals corresponding to the transmission of the symbols “1” or “0”

S ₁ , S ₁ or S ₂ , S ₃ ;

S ₃ , S ₁ or S ₄ , S ₃ ;

S ₁ , S ₂ or S ₂ , S ₄ ;

S ₃ , S ₂ or S ₄ , S ₄ .

In order to make a decision about the value of a symbol adopted at a k-symbol interval, it is necessary to determine with which of the indicated hypotheses the implementation of the received radio signal at k- and (k + 1) -character intervals is most correlated.

We denote the correlation integral of the product of the input signal and the i-reference signal on the k-symbol interval [kT, (k + 1) T] as

The integral taken on the following (k + 1) -interval [[k + 1) T, (k + 2) T] is denoted by

Then the rules for deciding on the reception of the characters "1" or "0" for signals from the MPM can be represented as follows:

Since inequalities always hold

a ₁ (k) = - a ₄ (k);

a ₂ (k) = - a ₃ (k);

a ₁ (k + 1) = - a ₄ (k + 1);

a ₂ (k + 1) = - a ₃ (k + 1),

then when receiving signals from the IMF, all four of the above decision rules are equivalent to one decision rule on the reception of the symbols "+1" or "-1"

In this case, the signal from the MFM can be taken as a signal from the MFM, and then carry out its relative decoding.

The input signal from the MUM (figure 2, a) is fed to the information inputs of the first and second correlators 2 and 3 and to the input of the synchronizer 1.

From the first and second reference outputs of the synchronizer 1 to the first and second inputs of the adder 6 and the subtraction unit 7, respectively, reference signals (FIG. 2, b and FIG. 2, c) are received that receive during even (k) and odd (k + 1 ) -characteristic value intervals

where A and φ ₀ are the amplitude and initial phase of the reference signals;

ω ₁ and ω ₂ are the circular frequencies of the reference signals;

0≤t * ≤Т - current time within one character interval.

The reference signal at the output of the subtraction block 6 for two consecutive odd (k-1) and even (k) -character intervals takes values

In this case, the reference signal at the output of the adder 7 for two consecutive even (k) and odd (k + 1) -symbolic intervals takes values

The reference signals from the outputs of the subtraction unit 6 and the adder 7 are fed to the reference inputs of the first and second correlators 2 and 3, whose clock inputs are respectively at the beginning of the odd (k + 1) and even k-symbol intervals from the second and third clock outputs of the synchronizer 1 arrive at a sequence of clock pulses (figure 2, g and figure 2, d) with a repetition period of 2T, shifted one relative to another by the duration of the symbol T.

As a result, the signal (figure 2, g) at the output of the first correlator 2 at the end of even k-symbol intervals takes the value

and the signal (figure 2, h) at the output of the second correlator 3 at the end of odd (k + 1) -symbolic intervals is the value

The indicated values of the output signals (see Fig. 2, g and 2, h) of the first and second correlators 2 and 3, supplied respectively to the information inputs of the first and second sampling / storage devices 4 and 5, are stored in the latter at the moment of arrival at their control inputs of the corresponding clock pulses (see figure 2, g and figure 2, e). After this, the values of the output signals (FIG. 2, and FIG. 2, k) of the first and second sampling / storage devices 4 and 5 are constant for two consecutive symbol intervals and are equal to the values of the corresponding correlation integrals

The signals (FIG. 2, and FIG. 2, k) from the outputs of the first and second sampling / storage devices 4 and 5 are supplied respectively to the first and second information inputs of the switch 8.

The output of the switch 8 passes a signal (see Fig. 2, i) or (see Fig. 2, k) from the outputs of the first or second sampling / storage devices 4 or 5, depending on which of the control inputs (the first or second) received the last clock pulse (see figure 2, g and figure 2, e) from the second or third clock output of the synchronizer 1.

As a result, during any (k + 2) -symbolic interval, a direct signal (figure 2, l) having the value

The comparator 9 compares the value of this signal with zero and implements the algorithm (1) for the optimal coherent reception of signals from the MPM.

At the output of the comparator 9, a signal is obtained (Fig. 2, m), the values of which are constant during any (k + 2) -character interval and are equal to the values of the received signal symbols with the MPM delayed by two symbol intervals.

The signal (see figure 2, m) from the output of the comparator 9 is fed to the first information output of the device, as well as to the information input of the relative decoder 10, the clock input of which from the third clock output of the synchronizer 1 receives a sequence of clock pulses (see figure 2 , f) with a period of T.

At the output of the relative decoder 10, a signal is obtained (FIG. 2, n), the values of which are constant during any symbol interval and are equal to the values of symbol estimates of the received signal with MFM delayed by two symbol intervals.

The signal (see figure 2, n) from the output of the relative decoder 10 is fed to the second information output of the device.

The clock output of the device from the third clock output of the synchronizer 1 serves clock pulses (see figure 2, e) with a repetition period T.

A device for receiving signals with minimal angular modulation can be implemented on known functional elements.

A possible example of the execution of the synchronizer 1 is shown in figure 4. The synchronizer 1 contains the first and second systems of the PHAGCH 11 and 12, the mixer 13, the low-pass filter 14, the amplifier-limiter 15, the separator 16 of the positive edges, the separator 17 of the negative edges and the element 18 OR. The outputs of the first and second PLLs 11 and 12 are respectively the first and second reference outputs of the synchronizer 1, the outputs of the isolators 16 and 17 of the positive and negative edges are the second and third clock outputs of the synchronizer 1, respectively, and the output of the 18 OR element is the first clock output of the synchronizer 1.

A possible example of the implementation of the relative decoder 10 is known from the prototype (see ed. St. USSR No. 801298, class H 04 L 27/14, 1981). According to the electrical structural diagram of the prototype shown in figure 5, the relative decoder contains a delay element 14 and the adder 15 modulo two (in the notation of the prototype).

The above information indicates the fulfillment of the following set of conditions when using the claimed technical solution:

- the proposed device is intended for use in industry, namely in communication technology, in particular in digital signal transmission systems with minimal angular modulation;

- for the claimed device in the form described in the independent clause of the claims, the possibility of its implementation using the means and methods described in the application or known prior to the priority date is confirmed.

Therefore, the claimed technical solution meets the criterion of "industrial applicability".

When using the proposed device for receiving signals with minimal angular modulation, the implementation of the optimal coherent reception of these signals, taking into account the correlation between their symbols, ensures improved fidelity of reception.

Claims (1)

A device for receiving signals with minimal angular modulation, comprising a synchronizer, first and second correlators, information inputs of which are connected to the device input, an adder, a subtraction unit, a comparator and a relative decoder, the clock input of which is connected to the first clock output of the synchronizer, characterized in that the first and second sampling / storage devices and a switch, the output of which is connected to the direct input of the comparator, whose inverse input is connected to the zero bus, and the output is the first inform the output of the device and connected to the information input of the relative decoder, the output of which is the second information output of the device, the clock output of which is connected to the first clock input of the synchronizer, the input of which is connected to the input of the device, the first and second reference outputs respectively to the first and second inputs of the adder and unit subtractions whose outputs are connected respectively to the reference inputs of the second and first correlators, the outputs of which are connected to the information inputs of the second and the first sampling / storage devices, the outputs of which are connected respectively to the second and first information inputs of the switch, the first and second control inputs of which are connected to the control inputs of the first and second sampling / storage devices, to the clock inputs of the first and second correlators, respectively, and the second and the third clock outputs of the synchronizer.

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