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ポータブル発電機 Com-Power CGO-515のPDF 取扱説明書をオンラインで閲覧またはダウンロードできます。Com-Power CGO-515 14 ページ。 Comb generators

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Com-Power CGO-515 取扱説明書
CGO-501, CGO-505 and CGO-515 Comb Generators
Page 9 of 14

Theory

The Comb Generator uses an impulse to generate its step frequency output. It uses a stable power supply and
signal shaping circuit to obtain relatively stable signal output with frequency components extending beyond 1 GHz.
The Comb Generator operates on battery power. The battery output is controlled by a voltage regulator circuit to
provide stable power output to the signal generating circuit. The signal generating circuit consists of a clock
generator, impulse generator, wave shaping circuit and output matching. The signal frequency is generated by a
crystal oscillator.
An impulse in time domain corresponds to a flat output across the entire frequency spectrum in frequency
domain. An ideal impulse, by definition is an infinite magnitude pulse with zero rise and fall time with zero
duration. Such a pulse is not practical; however, the Model CGO-501,505 and 515 Comb Generators use this
principle to get an output across a wide band. The highly stable frequency output from the oscillator is used to
generate an impulse with very short duration and sharp rise and fall times. The shaping circuit was designed for
improved stability, extended frequency response, and output impedance matching to 50 ohms. Since the circuit
cannot generate an ideal impulse with zero rise and fall times, the comb generator conducted output reduces at
the approximate rate of 20 dB per decade.
The radiated reference signal is transmitted by the antenna affixed to the top of the unit. An electrically short
monopole antenna is an antenna that is short compared to the wavelength of the frequency it radiates. Such an
antenna generates a radiated field proportional to its length. The radiated field, therefore, compensates for
decreasing signal up to a frequency, where the antenna cannot be called electrically short. This theory describes
the general behavior of the field, but each Comb Generator may behave slightly different than the other due to
circuit variation. Since the Comb Generators were designed to provide a reference reading at a given frequency,
this limitation is not a problem.
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Rev. 021020