Full modulation facilities are available with four ranges of FM and one of AM. The AM and FM controls are completely independent. This allows them to be set at any level from either the internal two frequency oscillator or an external signal. An internal oscillator output is also provided.
The output is selectable as a single range with a bank of seven thumbwheel switches. These thumbwheels enable the output frequency, to be dialled or reset to a resolution of 100Hz very quickly. They may be set in any order at any time and with any frequency step from the smallest (100Hz) to the largest (10 to 520MHz).
The output level controls are comprehensive. Two rotary switches give a total attenuation range of 119dB in 1dB steps. Dual output scales are provided giving simultaneous
indications of voltage pd and dBm. In addition an output meter displays the RF putput.
A very useful additional feature is the inclusion of a 1kHz automatic distortion meter. This allows the measurement of receiver SINAD ratios. SINAD is the ratio of signal plus noise plus
distortion to noise plus distortion.
The audio output from the receiver under test is automatically level sensed and the 1kHz fundamental removed. The meter then displays the SINAD ratio in dB.