A signal compensating network for use with a sensing element having different rates of response for increasing or decreasing sensed quantities includes a differentiating amplifier having different time constants for increasing and decreasing input signals. The output from the differentiating amplifier is combined with a signal representing the magnitude of the input signal to produce an output.
A circuit arrangement for deriving a control signal from an audio input signal for level-controlled audio systems comprises a first amplifier/comparator and a first silicon diode for coupling its output signal to a first circuit junction. A feedback circuit is provided for coupling the signal at the first circuit junction to the input of the first amplifier/comparator. A second amplifier/comparator is provided having its output coupled to a second silicon diode which passes its output signal to a second circuit junction. A first feedback resistor is provided to apply the signal at the second circuit junction to the input of the second amplifier/comparator and a second feedback resistor applies an output signal from the second amplifier/comparator to the input thereof. The arrangement is such that the audio input signal is applied to at least one of the first and second amplifier/comparators and one of the first and second circuit junctions is connected to a time constant circuit so that the signal applied thereto comprise linearly detected, unipolar halfwaves of the input signal. The first and second feedback resistors are chosen so that desired operating characteristics are obtained.
A wide bandwidth slope detector has a comparator with first and second time constant circulars coupled to first and second inputs thereof. Where one time constant is on the order of three times the other, the comparator will change state in response to the slopes of an input analog signal coupled to the time constant circuit. Feedback can be provided by a fixed resistor or by a tracking circuit. A smoothing or clipping circuit can be used to pre-process the input analog signals to eliminate noise therefrom. A bar code reading system combines first and second clipping circuits to smooth the highs and lows of the input signal, coupled to a slope detector. The tracking circuit can be used to provide a symmetrical hysteresis characteristic.
A wide bandwidth slope detector has a comparator with first and second time constant circuits coupled to first and second inputs thereof. Where one time constant is on the order of three times the other, the comparator will change state in response to the slopes of an input analog signal coupled to the time constant circuit. Feedback can be provided by a fixed resistor or by a tracking circuit. A smoothing or clipping circuit can be used to pre-process the input analog signals to eliminate noise therefrom. A bar code reading system combines first and second clipping circuits to smooth the highs and lows of the input signal, coupled to a slope detector. The tracking circuit can be used to provide a symmetrical hysteresis characteristic.
Improved accuracy in solution conductivity or resistivity measurment uses a center-sampling technique in which an AC drive is applied to a conductivity cell and the conductivity cell voltage is sampled during a predetermined time interval in the center of a half cycle drive waveform. The effects of cell capacitance, and particularly the electrode-solution capacitive, are compensated by periodically sampling during a second time interval which is different from the first interval. Based upon the difference between the sampled voltages in the first and second intervals, a correction to the measured conductivity or resistivity is made to compensate for capacitance induced errors.
