A high-frequency dynamic phase metering instrument for ionospheric research

A circuit for measuring the phase of signals returning from partial reflection processes in the ionosphere D region was built. The circuit was used at 1.5 MHz for which the maximum error was 3 degrees and has been tested at 10 MHz where the maximum error was found to be 6 degrees . The phase is measured with respect to a supplied constant reference voltage but the signal can range from less than 5 mV peak-to-peak to 3 V peak-to-peak. The output voltage is nearly linear with phase with 0 V corresponding to 0 degrees and -10 V corresponding to 180 degrees over a 100 kHz phase-modulation bandwidth.