초록 ▼

A dual threshold comparator circuit includes a comparator amplifier for comparing an analog input signal to a threshold waveform. The threshold waveform is generated in a circuit which includes positive and negative peak detector circuits and a slope detector circuit, all of which are connected to t

A dual threshold comparator circuit includes a comparator amplifier for comparing an analog input signal to a threshold waveform. The threshold waveform is generated in a circuit which includes positive and negative peak detector circuits and a slope detector circuit, all of which are connected to the analog signal source. A voltage divider is connected across the output of the positive and negative peak detector circuits. The threshold input to the comparator amplifier is connected to the common junction of first and second serially-connected impedances in the voltage divider. At the beginning of a particular half cycle of the analog input signal, the voltage across the voltage divider is equal to the difference of the most recent positive and negative peak voltages. The slope detector alters the effective impedances in the voltage divider to cause the threshold voltage to be equal to 25 or 75% of the total difference voltage, depending upon the slope of the analog signal.

대표청구항 ▼

For detecting transitions of an input signal between first and second states by comparison of the input signal to first and second adaptively derived threshold voltages, a circuit comprising: positive and negative peak detector circuits connected to the input signal source, said peak detector circui

For detecting transitions of an input signal between first and second states by comparison of the input signal to first and second adaptively derived threshold voltages, a circuit comprising: positive and negative peak detector circuits connected to the input signal source, said peak detector circuits providing output signals equal to the positive and negative peak voltages, respectively, of the input signal during two successive cycles, each of said peak detector circuits including a reset input; a slope detector circuit connected to the input signal source for providing an output voltage having a first value for positive slopes and a second value for negative slopes; an adaptive threshold-establishing circuit having a first input from said positive peak detector circuit, a second input from said negative peak detector circuit and a common output, said threshold-establishing circuit including a first impedance connecting said first input to said common output, a second impedance connecting said second input to said common output and means responsive to the value of the output from said slope detector circuit for changing the effective value of one of said impedances; comparator means connected to the input signal source and to the common output of said threshold-establishing circuit, said comparator means providing an output having a first state when the input signal is greater than the signal on the common output and a second state when the input signal is less than the signal on the common output; and means for applying the output of said comparator means to the reset inputs of said peak detector circuits to reset each peak detector whenever the comparator output changes to a state corresponding to the output of the peak detector to be reset.