TYPE 34200 STOCHASTICAL ANALVSER

ln addition to linear averaging, the other averaging
procedure applied by the analyser enables
the process parameter under test to be studied
continuously over a long period of time. The
exponential .,forgetting" typical of the analogue
RC complex, may be written with the help of
the follawing digital arithmetic procedure:
x. +
l ~
Subtroctor
-~
f ...
1
2K
'r!
Adde r
1 ..
1 Register 1--
Black diogram of exponentiol overogíng, K=4 through 15
r
ln the memory of the basic assembly, the result
function is represented by a function sector
consisting of 100 digital samples. ln the course
of the transformation to be carried out, the initio!
signal is regarded to be the periodic repetition
of that sector: the Fourier series of the
signal is generated. The actual frequency resolutien
to be obtained is equal to be reciprocal
of cycle time; the highest actual frequency ls,
as a rule, a hundred times thereof. To better
illustrate the result of transformation, the
number of frequency points may be selected to
be greater, too.
function
to be transformed
o cosine
multipller function
( 2n) cos N n · m
T = 1\ L t
-----,!'
weighting function
Of N sampled values, M=N/2 freq uency points
can be obtained. The m-th real or imaginary
frequency component can be obtained from the
follawing formulae:
N-1
Am= .2 xlnl)· w(nl)· cos l:._l_l) n·m
n= O \ N N N