| 摘要 |
The present invention relates to a method and a device for measuring and displaying the frequency response of a test object (1), such as an amplifier, tape recorder, whereby a known test signal (S) is transferred to the input of the test object (1) while the transmitted signal (U) is measured at the output of the test object, whereafter the measured frequency is displayed on a display means (2). According to the invention, the test signal (S) is comprised of a sine pulse train of different partial signals (D1, D2, D3, D4) with predetermined frequencies and with the same amplitudes. The different partial signals are detected at the output of the test object (1) by a completely independent detector unit (3) which continuously, within a whole or half period of the signal, reads the amplitude as well as the frequency. The frequency is detected by a frequency detector (4) comprised mainly of a zero passage detector (7) attached to a ramp function generator (8) and to a sample and hold circuit (9) to the input of which the output of the ramp function generator (8) is also attached. The amplitude is detected by a amplitude detector (5) comprised mainly of a full wave rectifier (14) attached to a peak-hold circuit (15). In addition, it is suitable, according to the invention, to have the output from the sample and hold circuit (9) and the output from the peak-hold circuit (15) attached to respective logarithmic amplifiers (10 respectively 16) which in turn are attached to the frequency, respectively amplitude, inputs, of the display means.
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