Abstract: In an electronic device and a method of correcting time-domain reflectometers, two channels of a time-domain reflectometer are connected to a corrector using cables, and the two channels are enabled to transmit pulses. Parameters Step Deskew and Channel Deskew of the two channels are zeroed. Resistance values of the two channels are measured simultaneously, and the value of the parameter Step Deskew of one of the two channels is adjusted according to the Resistance values of the two channels. Times of achieving the same resistance value of the two channels are measured after the cables and the connector have been disconnected, and the value of the parameter Channel Deskew of one of the two channels is adjusted according to the times of achieving the same resistance value. The adjusted values of the parameters Step Deskew and Channel Deskew are displayed through a display unit.

Abstract: In a method of measuring group delay (Tgd) of a device under test, an analog input signal having a predetermined period (T) is provided to the device under test so as to obtain a delayed output signal from the device under test. A phase difference is detected between first and second digital signals converted from the analog input signal and the delayed output signal, respectively. A current (I) corresponding to the phase difference flows through a circuit having a predetermined resistance (R) so as to result in a potential difference (?V). As such, the group delay (Tgd) of the device under test is determined as a function of the predetermined period (T), the current (I), the predetermined resistance (R), and the potential difference (?V). An apparatus for measuring the group delay (Tgd) of the device under test is also disclosed.

Abstract: A correction circuit for correcting the frequency of the output pulses produced by a gas flowmeter in dependence on the temperature of the gas comprises a control input for receiving a voltage representative of the difference between the temperature of the gas and a reference temperature. A voltage-controlled oscillator, operative during fixed short periods initiated by each flowmeter pulse, produces auxiliary pulses at a rate dependent on the voltage at the control input, and the auxiliary pulses are counted in a counter. Each time the counter counts a predetermined number of auxiliary pulses, it produces a signal which either blocks one flowmeter pulse or adds an additional pulse to the flowmeter pulses, in dependence on the polarity of the temperature difference.