| 摘要 |
<p>1,076,563. Circuits employing non-linear capacitors. CESKOSLOVENSKA AKADEMIE VED. July 3, 1964 [July 10, 1963 (4)], No. 27530/64. Heading H3B. An amplifier comprises a non-linear dielectric element C N (tandel) heated by a H.F. voltage G connected in series with a load Z 1 across a D.C. input, the output across the load Z 1 being applied over a resonant circuit O, tuned to an even harmonic of the H.F. supply frequency, to detector D and the output of the amplifier being developed across load Rd, Cd. In the absence of a D.C. input the voltage across the capacitor CN is distorted by the odd harmonics and as the D.C. input is increased the distortion is due to the even harmonics, Fig. 1 (not shown), which latter content causes the voltage across series or parallel resonant circuit O to increase. In order that the polarity of the output voltage is the same as that of the input voltage the arrangement of Fig. 3 (not shown) may be employed in which a second resonant circuit (O 1 ) tuned to an odd harmonic of the supply is connected across the load Z 1 and the rectified voltages appearing across the load circuits (Rd 1 ) (Cd 1 ), (Rd 2 ) (Cd 2 ) are subtracted. A bias source (B) is connected to the input circuit and is of such value that in the absence of the input voltage the output voltage is zero. In order to increase the band-width of the amplifier the dependence of the maximum value of the current through the dielectric element on the D.C. voltage applied may be employed, Fig. 4 (not shown). In the circuit of Fig. 5 (not shown), which is basically the same as that of Fig. 1, except that a voltage having a substantially lower frequency than the highfrequency heating voltage is superimposed on the heating voltage, a detector and load circuit is inserted between the load impedance Z 1 and resonant circuit. The voltage appearing across impedance Z 1 represents the voltage form of the high-frequency current which is modulated in the absence of a D.C. input voltage by a signal of twice the frequency of the superimposed L.F. component of the heating voltage. As the D.C. input voltage increases the high-frequency current is modulated by a signal with growing content of the modulating low-frequency component, the modulation envelope being demodulated by the detector and the series or parallel tuned circuit being tuned to the modulating low frequency. The increase of the resonant voltage in the resonant circuit appears as a D.C. output voltage across impedance Rd 2 Cd 2 . In order for the amplifier to follow any change of polarity of the input voltage two parallel or series resonant circuits may be employed, Fig. 6 (not shown), one circuit being tuned to the fundamental component of the modulating low-frequency signal and the second resonant circuit to the second harmonic of the low frequency.</p> |
