| 摘要 |
An analog to digital convertor includes a pulse width modulated circuit (PWM) responsive to an analog parameter of an analog signal. The PWM circuit generates a pulse having a duty cycle proportional to the analog parameter. A counter generates a plurality of counterpulses during the pulse duty cycle and a sub-cycle pulse generator generates a series of subcycle pulses during each of the counterpulses. A latch circuit latches the state of the subcycle pulse generator at a predetermined time relative to the termination of the PWM pulse and a logic circuit counts the number of counterpulses which are generated during the PWM pulse. A most significant bit number is represented by the number of counter-pulses and a least significant bit number is determined by the state of the subcycle pulses in the latch. These two numbers added together provide a digital number representative of the analog parameter. |
