| Popis: |
The article presents the results of studies of the pulse and harmonic signals shapers that is a part of measuring instruments with adjustable parameters. A method is proposed for shaping pulse signals via a harmonic signal as a reference, associated with the use of a stroboscopic sample-and-hold circuit. For shaping of the output signal the relative method of setting the amplitude has been used, which (though lacking speed) allows to get rid of the error components due to the irregularity of the frequency response and the mismatch in the output node. In this case, the output signal and its nominal level are measured in the same sectional plane of the output node. A shaper of harmonic and pulse signals, which implements the phase readout method based on a stroboscopic converter with feedback, is characterized by a significant reduction in the effect of broadband interference on the transformation accuracy. The use of a two-channel shaper structure is proposed. If channels are identical, the structure made it possible to minimize the error due to the amplitude and time instability of stroboscopic pulses. In the shaper the gating is performed at the extreme points, and in each channel, the gating of extreme value of only one sign, which is different from the extreme sign in the other channel. A number of studies have been carried out related to the estimation of the amplitude-frequency error due to the responsiveness of nonlinear elements in ring mixers in stroboscopic sample-and-hold circuits. The influence of operating conditions and mixer parts on its parameters is studied. The verification of the obtained results of theoretical research has been carried out via numerical modeling and experimentally. The influence of the parameters of the mixer parts on the accuracy of the stroboscopic sample-and-hold circuit has been evaluated |
