SU755155A1 - Method and device for synchronizing multichannel communication systems with mutually orthogonal channel signals and phase difference modulation - Google Patents

Description

one

The invention relates to radio engineering and may be used in multi-channel communication systems with modulation phase difference and mutually-orthogonal channel signals _ tional for pe- ³ soap has discrete information.

A known method of synchronization of multichannel communication systems with mutually orthogonal channel signals and phase-difference modulation consists in determining the voltage of the difference of the squares of the amplitudes of the input signal measured on neighboring messages and generating a correction signal for the clock channel frequencies [1]. (15

It is also known a device for implementing this method, which contains channel filters combined at the input, the outputs of which through 20 are connected in series differential “amplifier and absolute magnitude of the difference of amplitudes definition unit, are connected to the information input: _ _{from the} node of the definition of the correction sign [2]. · * >

However, this method and device

for its implementation do not provide sufficient noise immunity

reception. thirty

2

The purpose of the invention is to improve the noise immunity of the reception by improving the accuracy of sync.

To do this, in the method of synchronization of multichannel communication systems with mutually orthogonal channel signals and phase-difference modulation, we will determine the voltage difference of the quadrature amplitudes of the input signal ,. from the neighboring messages and generating a correction signal for channel clock frequencies, preliminarily shift the clock frequencies at the reception relative to the clock frequencies in the transmission on a given wavelength, and to generate a correction signal the difference voltage of the squares of the input signal amplitudes the premises are compared with a predetermined permissible out-of-sync voltage, and if it is exceeded, a one-digit correction signal is produced.

In the device for implementing the method containing the combined. the input channel filters, the outputs of which are connected through a series-connected differential amplifier and a unit for determining the absolute magnitude of the difference of amplitudes are connected to

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the information input of the correction sign determination node is entered in series with the group signal envelope rectifier and storage integrator, while the input of the group signal envelope rectifier is connected to the combined input of the channel filters, and the output of the integrator accumulator is connected to the reference input of the correction sign definition node.

FIG. 1 shows a device for the implementation of the proposed method; FIG. 2 shows time diagrams explaining the proposed method.

Pre-shift the clock frequencies at the reception relative to the clock frequencies at the transmission of a given amount A А, determined by the quality of the channel and the correction step, and at the reception set the voltage of the permissible out-of-sync AND _0P corresponding to the specified accuracy of the phase for the channel, and the difference voltage B calculated as the difference the voltages of a pair of signals yupredёmyemyh ~ on two adjacent premises, compared with and _op and only when it is exceeded produce a signal of one sign correction, which compensate cosiness is the amount of desynchronization caused by both a preliminary shift of clock frequencies and external destabilizing factors, and stops the correction until the next excess in 'above υ _ση . The clock shift of the oscillators of the receiver and transmitter is selected, on the one hand, from the point of view of the effective operation of the synchronization device during

the presence of interference and, on the other hand, the possibility of compensating for this artificially introduced frequency difference due to one-step correction A · Definition

^can be found by comparing the expressions for the generator frequency at the transmission (<U | rd,) ^and reception ( _ηρΜ ), taking into account the specific step of AT correction, / carried out each sprinkling (T) and the division factor of the frequency dividers (K) at the transmission and reception i.e.

. - _ _g - _ k and & t

^s ητ, αχ- PfP. prd-γ ·. ^ _t '-c _t _d _T )

The reliability of the synchronization operation assumes that the divergence of the clock frequencies on the transmission and reception should not exceed the values

Thus, the work of one-digit synchronization consists of two stages: the stage of entering synchronism and the stage of maintaining synphasicity. In the first stage, the value of B ¹ exceeds ^both op and each parcel produces the same correction sign until the system is phased, i.e. In ¹ will not be less. After

This correction is turned off and the phase mismatch of the clock frequencies on the transmission and reception is calculated by the valid value (and _OG) and is determined by the selected value and the quality of the channel. The time and during which no correction is made can be adjusted by setting the initial value and _op .

The moments of manipulation on the transmission occur at the boundaries of the parcels T _pr d, and the moments of recovery at the reception TPRM. The time & ι is characterized by the tolerance and adjustable value of the in-phase accuracy between the moments of the one-digit correction off in the region of point b ¹ , and the instants of this correction in the region of the point o. Adjustment A ί is performed for a specific channel by choosing the value of D V.

The proposed device for implementing the described method contains channel filters 1 and 2, the output of which is fed to the input group signal, and the outputs of each of which are connected to the input of the differential amplifier 3, the output of which includes unit 4 for determining the absolute magnitude of the difference of amplitudes to which the information input is connected node 5 to determine the sign of the correction. The rectifier 6 of the envelope of the group signal and the drive-integrator 7 are connected in series.

A device for implementing the application method works as follows.

Channel filters 1 and 2 determine the amplitudes of one of the channel signals, and filter 1 determines the amplitude of the signal on odd data transmissions, and filter 2 on even ones. The amplitudes from the channel filters 1 and 2 are fed to the input of the differential amplifier 3, the output signal from which is the input difference, i.e. In ^! . At the output of the differential amplifier 3, a block 4 is connected to the information input of node 5-, in which the value \ В ¹ 1 is compared with voltage 1 and _{0Г (} 1. The voltage produced by the rectifier 6 is fed to the input of the storage integrator input group signal is given.

. If the signal value of 5 V'1 is exceeded over the signal value (b) _op ), the generation of a correction signal from node 5 is allowed, each parcel is corrected by a one-digit correction.

When turning the same signal values | above the signal value (in '1, the prohibition of issuing one-digit corrections is prohibited until the next change in the ratio between the two voltages | V ⁽ | and 1 and ^]. With the deterioration of the interfering environment in the channel, the interference also acts on the high path

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calculating the value | υ _οη | , and on the path of calculation | In ¹ 1, by virtue of which the change in the level and nature of interference does not affect the initial setting υ _οη , which characterizes the necessary accuracy of the phase response.

The invention improves the accuracy of reception and noise immunity of the reception, as well as reduce the number of integrated circuits, analog switches and integrators spent on the implementation of the proposed device. -

Claims (2)

Claim 1. The method of synchronization of multichannel communication systems with mutually orthogonal channel signals and phase-difference modulation, which consists in determining the voltage of the difference of the squares of the amplitudes of the input signal measured on adjacent premises / and generating a correction signal for the clock frequency frequencies, characterized in that increase the noise immunity of the reception by increasing the accuracy of the synchronization, pre-shift the clock frequencies at the reception relative to the clock frequencies on the transmission by a specified amount , and to generate a correction signal, the voltage of the difference of the squares of the amplitudes of the input signal, measured on neighboring premises, is compared with a predetermined voltage of the permissible out-of-sync, and when it is exceeded, a single-digit correction signal is produced. 2. A device for implementing the method according to claim 1, containing integrated on the input channel filters, , 0 whose outputs are connected via a serially connected differential amplifier and an absolute magnitude difference determination unit of the amplitude difference connected to the information input of the correction sign determination unit, which is entered by the series-connected rectifier of the group signal and the accumulator integrator, while the rectifier input of the curve bend The group signal is connected to the combined input of the channel filters, and the drive of the integrator drive is connected to the reference input of the correction sign determination unit. 25