SU1580267A1 - Apparatus for determining mean value of sample sequence - Google Patents

Abstract

The invention relates to a measurement technique and can be used to process signals in determining an average value in the presence of interference. The purpose of the invention is to increase speed by replacing the multiplication operation with the summation operation - accumulation. The device includes three series-connected averaging totalizer accumulators 1 - 3, the outputs of the second 2 and third 3 are connected to the inputs of the subtractor 4, the output of which is the output of the device. The synchronization of the operation of the drives is provided by the synchronization unit 5, built on the delay elements 6 and 7. 1 sludge.

Description

The invention relates to the field of signal processing and can be used in measuring technique when determining the average value of signals in the presence of interference.

The purpose of the invention is to increase the processing speed of digital signals when determining the average value of a sequence of samples by replacing the operation of multiplication by the operation of summation-accumulation.

Pa drawing shows a functional diagram of the device.

A device for determining the average value of the “sampling sequence” contains connected to the signal input of the device, the first 1, second 2, third 3 averaging drives and e-reader 4 connected in series, the second input of which is connected to the output of the second averaging about drive 2, and the output is an output device, to the synchronization input of the device is connected to the synchronization block 5, including series-connected delay elements 6 and 7, the outputs of the synchronization block 5 are connected to the clocking inputs drives 1-3. thirty

The device operates as follows.

at once.

Synchronization unit 5 implements clock pulses at the synchro inputs of averaging drives 1 - 3. The value, • delay of pulses at the outputs of delay elements 6 and 7, is selected from the conditions for the end of transient processes, respectively, in averaging drives 1 and 2 when the next clock pulse arrives at them ..

Define the frequency response of the device. Let the input of the device receive a sequence of samples of the harmonic signal where U, f, t cn ’=

>> “(1) uCt ^ .UsinCZ'nft + q”) in the form.

U (n) = Usin (2 ^> nf t'n + cp) (2) respectively amplitude, frequency, 'phase of the harmonic signal;

sampling repetition period;

phase shift.

To reduce the calculations, we put U = 1.

The averaging accumulator performs the function of summing, therefore, at the output of accumulator 1, the sum of N samples of signal (2) can be defined ^as Ν-1

U <(N) = ^ lsin (2 ''fk'n + tf) ^e _sin (UM-C (N-1) / 21 2nfg) _g . / y _s s in? fc miccosCi-'iifc + ZwNfT ')' 2sinTf '2sinTf? ”

M-t = Xu (n).

n * -o

The signal (3) from the output of the drive 1 is fed to the input of the output of the last border is

M- <

(3) drive 2, per signal with a volume of u ¹ Ν-ι _g *. ~.

υ ₂ (») .χ _{0 |} (η) -ΖΓ | 2? ^ 12 n ^ b [2sinifc _ £ 221111) ί f Cu) 1 _w c os (cp-'ii'fi ')

2sin'nf ^ 'J 2sin' 'f?' _ -2121 ___ sin (<£ + 2ufi-N) ~ 4sin7 £ fN ’

The signal (4) from the output of drive 2 · goes to drive 3, the output of which ultimately generates a signal of the form _Nsin if,

4sin ^ f Τ '(4) (5)

Signals (4) and (5) from the outputs of drives 2 and 3 are fed to subtractor 4 with weights equal to 1 and 2 / N, respectively. As a result, the signal at the output of the subtractor 4 has the form. U ₊ (N) = U _a (N) -> U ₃ (N) = sin (cp + --- 2 ^/ ! I'f b) sinN'ii'f £ “rd ⁵ ?? Τ '~ · sinCf + N'i'f c') cosN '»fi''~ 4sin ^? ffT ”~ * (6), From the analysis of expression (6) it follows that with averaging over cp uniformly distributed over an interval of 2% and with a decrease in the sampling period?

in the passage to the limit at? - »0 expression (6) takes the following form:

lira ΐ- * 0 7 2x ² (. x sin (<f + x) cosx1 _№ sin (<? + x), sinx —_ J = 2x ^ “x

-cosx), (7) where x = Nfrf ?.

Thus, the frequency response of this device is similar to the frequency response of the known device _{G (x} ). 5i <p! Fl (“nz _ _cozy)>

Y, where y = G) t;

GO is the circular frequency.

Note that devices with a frequency response (8) have low sensitivity to high-frequency components of the spectrum, the frequency parameters of which satisfy the ratio Nf £> 1, which leads to an increase in the accuracy of estimating the average value under conditions of high-frequency interference.

Claims (1)

Claim Device for determining medium 5 of it the values of the sequence of samples containing the first averaging drive, the input of which is connected to the input of the device, the second averaging. a drive that distinguishes 10 with the fact that in order to improve performance, a third averaging drive, a subtractor and a synchronization unit are introduced into it, the output of the first averaging drive is connected 15 to the input of the second averaging drive, the output of which is connected to the first input of the subtractor and the input of the third averaging drive, the output of which is connected to the second input of the subtractor, the output of which is the output of the device, and the clock outputs of the averaging drives are connected to the corresponding outputs of the synchronization unit, the input of which 25 is connected to the device sync input.