Digital C/kT Meter.
DEPARTMENT OF THE NAVY WASHINGTON D C
Pagination or Media Count:
A digital CkT meter is described for measuring the ratio of carrier power to noise power in a one Hz bandwidth and provide the results to a continuous read-out digital display. The circuit receives an input signal from the i-f amplifier prior to demodulation. The signal is amplified and fed to a mixer where it is converted down to a lower frequency. The mixer supplies the signal to a power divider through a voltage controlled attenuator where the signal is split into a noise power channel and a carrier power channel. The noise signal is filtered, amplified and fed to a detectoramplifier. The output of the detectoramplifier is integrated and fed back to the voltage controlled attenuator to form an automatic gain control feedback loop such that the noise power level output of the bandpass filter and amplifier is held constant. The result is that the log of the voltage drop across the resistor is directly proportional to the ratio of carrier power to noise power and is employed to actuate a digital display.
- Test Facilities, Equipment and Methods