| 摘要 |
1,204,980. Pulse modulation circuit.; transistor monostable circuits. P. R. MALLORY & CO. Inc. 8 Nov., 1967, No. 50487/69. Headings H3T and H4L. In a pulse-width modulator the duty cycle of a monostable device comprising transistors T11, T12 is varied by an input signal applied at terminal 50 while the repetition rate as controlled by frequency negative-going pulses pulses applied at terminal 41 remains constant. The output is supplied via amplifiers 30 comprising complementary transistors T31, T33 and T32, T34, respectively, and charging current for the timing capacitor C11 is supplied via the low saturation resistance of transistor T31 and diode D11, enabling a higher repetition rate to be used. Transistors T21, T23 act as constant current devices. |
