RU2071181C1 - Synchronization method in devices for transmission of digital information - Google Patents

Abstract

FIELD: radio communication, devices for transmission of digital information. SUBSTANCE: method involves generation of code sequence of information to be transmitted using clock synchronization signals and sending this sequence to air. Receiving part of device receives radio signals, amplifies and detects them. Signals of code sequence are transmitted by signals with varied duration. Received code sequence at receiving part is delayed by $$$, which conforms to condition $$$, while $$$, where $$$ and T are signals with greater duration, lesser duration and transition for repeating signals of clock synchronization, respectively. Leading edge of delayed signals is forwarded by additional signals with duration $$$. If said signals match received signals, then signals are detected for generation of code sequence of transmitted information. EFFECT: increased precision of synchronization, increased stability to noise, keeping time for synchronization initialization. 3 dwg

Description

 The invention relates to techniques for transmitting discrete information and can be used in radio communication systems for synchronization on the premises (pulses) of the receiving and transmitting parts of the system.

There is a method of synchronization by sendings and cycles in discrete message transmission systems, based on the formation on the transmitting side of the clock pulses of the code sequence of the transmitted information message and synchronization pulses, and on the receiving side, the synchronization pulses are allocated in accordance with which phase adjustment of the local clock pulses is performed, registering the received signals of an informational message, and adjusting the repetition rate of clock pulses [1]
The disadvantage of this method is the dependence of the correcting ability of the system on the degree of distortion of the synchronizing pulse, the additional time for establishing synchronism and the dependence of the accuracy of synchronization on the length of the code combinations due to the finite stability of local clocks on the transmitting and receiving parts of the system.

There is a method of synchronization by sendings, according to which the received signal is gated by two reference signals, one of which is delayed by half of the elementary signal relative to the other, the durations of the signals obtained after gating are determined, each of which is compared with the duration of the elementary signal, invert the signal, the duration of which is less than half the duration elementary premise, then the received signals are compared with each other and according to the results of the comparison, the reference signals are shifted and a given tuning step, the received and reference signals are additionally inverted, the received inverted signal is gated by each inverted reference signal, each additional signal received after gating is summed with the signal received after gating by the corresponding reference signal, each of the received total signals is gated by an additional reference signal delayed relative to the corresponding reference signal by a quarter of the chip, with the shift of the reference signals and additional Yelnia reference signal is carried out as to whether the reference signal from which the received signal after gating shorter duration [2]
The disadvantage of this method is the dependence of the correcting ability of the system on the degree of distortion of synchronizing pulses, additional time for establishing synchronism, as well as low speed of information transfer, complexity of technical implementation and low reliability due to the need to introduce a large number of delays, which generally reduces the technical capabilities of the known method in radio communication systems for synchronization in the transmission of discrete messages.

 The technical result of the method eliminates the time of entry into synchronism, improving the accuracy of synchronization and noise immunity in the transmission of discrete quantized messages.

The technical result is achieved by the fact that in the synchronization method in discrete message transmission systems, based on the formation on the transmitting side of the clock synchronization signals of the code sequence of the transmitted message and its broadcasting, and on the receiving side, receiving radio signals, amplifying them, detecting and extracting synchronization signals and the transmitted message, the transmission of code information signals is carried out by signals of different durations corresponding, for example, to the levels of Log. 1 and (or) Log. 0, selected at the receiving side signals delayed by the time τ _h ,, which is selected from the condition τ _1> τ _{2 s} ≥τ while (τ ₁ + τ ₂₎ ≅T ,, where τ _1, τ _2, signal duration correspondingly more the duration, with a short duration and the period of repetition of the probing signals, on the leading edge of the delayed signals generate additional signals with a duration of τ _d ≅ τ ₂ and take them for clock synchronization signals, which coincide with the received signals to distinguish the code sequence signals of the transmitted message.

 Figure 1 presents the plot of stresses and timing diagrams explaining the proposed method of synchronization; figure 2 presents a functional diagram of the transmitting side of the synchronization device; figure 3 of the receiving side of the synchronization device.

 The synchronization method in discrete message transmission systems is as follows.

On the transmitting side of the system for transmitting discrete messages by clock signals (Fig. 1, a) with a repetition period T, a code sequence of the transmitted message is formed (Fig. 1, b) and emitted into the air by signals of different durations (Fig. 1, d). So, for example, Log.1 levels of the transmitted message shown in FIG. 1b, are emitted into the air by signals with a duration of τ ₁ (FIG. 1, c), and Log 0 levels with a duration of τ ₂ (FIG. 1, d). Moreover, the durations of τ ₁ and τ ₂ are chosen so that τ ₁ > τ ₂ , and (τ ₁ + τ ₂ ) ≅ T. Thus, in the transmitter of the discrete message transmission system, a sequence of signals with different durations is formed (Fig. 1d), which contains information about the transmitted message, the frequency and repetition period of the clock synchronization signals of the transmitter. Figure 1 conditionally shows that the duration of the clock synchronization signal (figure 1, a) is T.

 On the receiving side of the discrete message transmission system, the signals (Fig. 1, g) transmitted on the air are received, amplified, detected and isolated as a sequence of signals of different durations (Fig. 1, g). The transmitted and received signals in the accompanying drawings are conventionally represented by the same diagrams shown in figure 1,

The signals extracted at the receiving side (FIG. 1, d) are delayed for a time τ _s (FIG. 1, d), which is selected from the condition τ ₁ > τ _s ≥ τ ₂ ,, and clock signals are generated on the leading edge of the delayed signals ( figure 1, e) with a duration of τ _d ≅τ ₂ ..

 By the coincidence of the clock synchronization signals (Fig. 1, e) with the received signals (Fig. 1, d), signals are generated (Fig. 1, g), according to which the code signals are generated from the clock synchronization signals (Fig. 1, g). the sequence of the transmitted message (figure 1, h).

The transmitting (Fig. 2) and receiving (Fig. 3) synchronization devices that implement the synchronization method on the premises in discrete message transmission systems, contains:
on the transmitting side, a clock generator 1, a parallel-serial register 1 clock, a parallel-serial shift register 2, driver 3 pulses, control unit 4, element 2 OR 5, element 2 AND 6 and transmitter 7;
on the receiving side, a receiver 8, a serial-parallel shift register 9, a delay element 10, an element 2I 11, a pulse shaper 12, a control unit 13.

 The synchronization device operates as follows.

According to the clock sync pulses (Fig. 1, a) of the generator 1 at the output of the parallel-serial register 2 from the n-bit parallel code of the transmitted message generated at the information inputs of the register 1, a sequence of n-bit pulses is generated (Fig. 1, b), according to the leading edge of which the shaper 3 generates pulses (Fig. 1, c) of duration τ ₁ .. From the output of the shaper 3 pulses (Fig. 1, c) are fed to one of the inputs of element 2 OR 5, to the other input of which pulses from the output of the generator 1, while the output of the electric ment 2 OR 5 formed pulse sequence shown in FIG. 1, g. If there is a level of Log.1 at the second input of element 2I 6, the pulse train from the output of element 2 OR 5 through element 2I 6 goes to the input of the modulator of the transmitter 7, which, in accordance with the modulation pulses (Fig. 1, d), broadcasts radio signals different durations.

 The operation mode of the transmitting side of the device is set by the control unit 4, which includes pulse counters and decoders on logical elements not shown in the drawing. After passing through the n-pulses from the generator 1 at the first output of the control unit 4, a “Reset” pulse is generated, by which the parallel-serial register 2 is set at the input R to the initial state and in it again, according to the pulses of the generator 1, the n-bit parallel code is converted to n- discharge sequence of pulses. At the output 2 of the control unit 4, pulses are formed, which determine the duration of the transmitting side of the device, for example, in cycles.

 On the receiving side, the receiver 8 receives radio signals, their amplification and detection. In the accompanying drawings, the signals projected by the receiver 8 are conventionally shown in 1, g.

The signals from the output of the receiver 8 are delayed in the delay element 10 for a time τ _s (Fig. 1, d) and are fed to the input of the shaper 12, at the output of which pulses of duration τ _d ≅τ ₂ are formed along the leading edge of the input pulses (Fig. 1, e ) The formation of such pulses is necessary to eliminate malfunctions in the operation of the discrete message transmission system with increasing τ _s . The pulses from the output of the shaper 12 are used as clock synchronization signals to control the operation of the serial-parallel register 9 and the control unit 13. By the coincidence of the signals from the output of the receiver 8 (Fig. 1, d) with the signals of the driver 12 (Fig. 1, e) at the inputs of the element 2I 11, the pulses shown in Fig. 1, g, which are generated by the clock synchronization pulses, are formed at the output of the latter (Fig. 1, e) are written in parallel-serial register 9, the output of which is formed by n-bit parallel code of the transmitted message.

 The control unit 13 is made similar to the control unit 4 of the transmitting side of the device. At the output of the control unit 13 through pulses of the shaper 12, pulses are generated to reset the register 9 to zero (in the accompanying drawings, the pulses are "reset" of the control unit 13 (not shown).

Claims (1)

The synchronization method in discrete message transmission systems, based on the formation on the transmitting side of the clock synchronization signals of the code sequence of the transmitted message and its broadcasting, and on the receiving side of the reception of radio signals, their amplification and detection, characterized in that the transmission of the code sequence of the transmitted message carry out signals of different durations, and the received code sequence on the receiving side is delayed by a time τ _s , which is chosen from conditions τ ₁ > τ _s ≥ τ ₂ , with (τ ₁ + τ ₂ ) ≅ T, where τ ₁ , τ ₂ and T, respectively, the duration of the signals with a longer duration, with a short duration and the repetition period of the clock synchronization signals, on the leading edge delayed signals generate additional signals of duration τ _d ≅ τ ₂ by coincidence of which with the received signals they emit signals, which form the code sequence of the transmitted message.

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