| Summary: | 碩士 === 國立交通大學 === 光電(科學)研究所 === 83 === At present,frequency counter is the most accurate instrument
for measuring signal frequency.Since such counter consists of a
digital logic circuit,the upper limit of countable frequency
will be limited by the response speed of this circuit.Although
some strategies of transformation do increase this upper limit
a little ,the situation is not much improved.In our experiment,
we adopt the fast speed electronic devices(photoconductive)
switch instead of the usual devices.such novel counter,we study
the countable frequency range,sensitivity and stability of the
system and the accuracy of measurement. So far our counter can
count signal frequency more then 3.5 GHz with sensitivity 1dBm
and the input signal frequency modulation tolerance can attain
40MHz,the accuracy of frequency attains the order of Hz .
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