| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a detection output in real time, without having to depend on the phase of an input signal, without accompanying ripples and without delays. SOLUTION: The input signal f(t) and the local cosωct and local sinωct of the center frequency of a band desired to be detected are mixed by using mixers 15 and 17, the sum f(t)×(cosωct+sinωct) and the difference f(t)×(cosωct-sinωct) of the both outputs of the mixers 15 and 17 are calculated; the sum output and the difference output are made to pass through respective low-pass filters 24 and 25 which define the interval between the center frequency and one end of bandwidth as a cutoff frequency, the filter outputs are squared and added; and the added output is defined as a detection output.</p> |
