SU554629A1 - D-sequence sync device - Google Patents

Description

one

The invention relates to radio engineering and can be used in communication systems and radar systems.

A D-sequence synchronization device is known that contains a correlator, one input of which is connected to a generator through a clock unit and a delay tracking unit, and through a compensation unit to the inputs of the first and second threshold elements, the outputs of which are connected respectively to the inputs of the output signal generator and the unit control, the other input of which is connected to the output of the delay tracking unit, and the corresponding outputs of the control unit are connected to the inputs of the output driver, the correlator and clock unit directly and through the generator - with the inputs of the block for tracking the delay and the correlator.

However, the known device has a large time to synchronize.

In order to reduce the synchronization time, the proposed D-sequence synchronization device introduces the adder of negative mutual correlation functions (VKF), the adder of positive VKF, the adder of VKF modules and the third threshold element, with the corresponding outputs of the correlator through the adder of negative VKF and the adder of positive

VKF connected to the first and second threshold elements and the adder modules VKF, the output of which through the third threshold element is connected to the auxiliary input

the control unit, the corresponding outputs of which are connected to the inputs of the adder modules VKF, the adder negative VKF, the adder positive VKF and the second input of the third threshold element, the third

the input of which is connected to the output of the compensation block.

The drawing shows a block diagram of the device. The D-sequence synchronization device contains a correlator 1, one input of which is connected to generator 4 through clock unit 2 and delay tracking unit 3, and through compensation block 5 to the inputs of the first and second threshold elements 6 and 7, outputs

which are connected respectively to the inputs of the imager 8 output signals and the control unit 9, the other input of the latter is connected to the output of the block 3: for a delay, and the corresponding outputs of the control unit 9 of the control with the inputs of the imager 8 output signals, the correlator 1 and the clock unit 2 directly and through generator 4 - with the inputs of the block 3 for tracking the delay and the correlator of torus 1, as well as the adder

10 negative CCFs, an adder 11 positive BKFs, an adder 12 ICF modules and a third threshold element 13, with the corresponding outputs of the correlator 1 through an adder 10 negative ICFs and an adder 11 positive ICFs connected to the first and second threshold elements 6 and 7 and the adder 12 modules VKF, its output through the third threshold element 13 is connected to the input of control block 9, the corresponding outputs of which are connected to the inputs of the adder 12 of the modules of the VKF, the adder 10 negative VKF, the adder 11 positive BKF and the second input of the third the threshold element 13, the third input of which is connected to the output of block 5 compensation.

The device works as follows.

At the first stage, the shift is carried out relative to the received reference D-sequence, and the values of the function of the sum of modules (FSM) R (n, m, t) of the private mutual correlation functions of the D-sequences are calculated.

Mathematically, FSM is described by

2P-t 1

pack

y (. + t) xX

2

X (+ t),

where y (i), x (i) are the discretes of the received and reference D-sequences, respectively;

t is the relative time shift;

“Log2A;

N is the number of discretes in the period of the sequence;

from -1,2, ..., (l-1).

The function R (n, t, t) has the following functions: periodically alternating maximum and zero values, separated from one another at a distance of 2 ™ Ti; the maximum outliers for any of have the same values and equal in magnitude to the peak of the autocorrelation function of the D-sequence; with full synchronism of the received and reference D-sequences, all partial mutually-correlation functions, mathematically described by the integral of the expression for the function R (n, t, t), have the same signs; the values of intermediate emissions of the function R (n, t, t) decrease with increasing from.

The shift is carried out at time intervals equal to the duration of the sequence by the value of the duration of the discrete TU.

In order to calculate the function R (n, t, t), the numbers accumulated in correlator 1 with a period of 2 ° 1 are either transmitted to the adder of 10 negative CCFs (if the CCF are negative), or to the adder 11 positive CCFs (if the CCF are positive). The adders 10 and 11 negative and positive CCFs with a period equal to the duration of the sequence are counted by the control block 9, and the numbers accumulated in them add up to

module in the adder 12 modules VKF. If the accumulated sums in the adders 10–12 negative, positive, and VCF modules do not exceed the threshold levels set by threshold elements 6, 7, and 13, then the device shifts the reference sequence by one discretion, and the procedure for calculating the function R (n, t, t) is repeated.

If the threshold level is exceeded by the threshold element 6 (7), then from this threshold element a complete synchronism signal is sent to the control block 9, the search is completed and the driver

The 8 output signals begin to process information from the threshold elements 6 and 7.

If the excess of the threshold level is fixed only by the threshold element 13, then

The control unit 9 is signaled about the presence of relative synchronism, the period for retrieving information from the correlator 1 is doubled, i.e. the device proceeds to the next stage of the search. Calculating values

the functions R (n, t, t) are repeated again, and if the threshold element 13 only detects an excess of the threshold level, the polling period of the correlator 1 is doubled again, i.e. the device proceeds to the next stage of the search. In the absence of threshold crossing after polling threshold elements 6, 7 and 13, before proceeding to the next stage, the reference sequence shifts relative to the received one by an amount equal to the polling period of the correlator 1.

The search process lasts until the threshold is exceeded in the threshold elements 6 (7) or until the polling period of the correlator 1 becomes equal, which establishes the fact of complete synchronism, and consequently, the threshold is exceeded in the threshold elements 6 (7) . If this does not happen, the search is repeated with

the beginning.

Since the establishment of full synchronization, the delay tracking unit 3 is entered into the tracking mode, the clock unit 2 is turned off, and the received discrete information is output at the device output.

Thus, as soon as the accepted and reference D-sequences are in synchronism, the device begins to provide information.

Claims (1)

Invention Formula A D-sequence synchronization device containing a correlator, one input of which is connected to the generator through a clock unit and a delay tracking unit, and through a compensation unit to the inputs of the first and second threshold elements, the outputs of which are connected respectively to the inputs of the output signal generator and the control unit , the other input of which is connected to the output of the delay tracking unit, and the corresponding outputs of the control unit are connected to the inputs of the output driver, the correlator and the clock unit mediocre and through a generator with inputs of a delay tracking unit and a correlator, characterized in that, in order to reduce synchronization time, a summator of negative correlation functions (ICF), an adder of positive ICF, an adder of ICF modules and the third threshold element are entered into the device at In this regard, the corresponding correlator outputs are connected through the negative VKF adder and the positive VKF adder connected to the first and second threshold elements and the VKF module adder, the output of which is connected via the third threshold element to the auxiliary control unit input, which outputs are connected to the adder inputs of the VKF module. VKF, adder positive VKF and the second input of the third threshold element, the third input of which is connected to the output of the compensation block.