The MH680A tracking generator is a sweep signal source which when used with the MS2601A permits direct observation and measurement of frequency characteristics over 100 kHz to 2 GHz. A high performance ALC (automatic level control) circuit is provided, the output level deviation is small and transmission characteristics can be measured with high accuracy. The MH680A has a frequency range of 10 kHz - 2 GHz and an output level of 0 dBm, with a 10 dB analogue attenuator for adjustment. To allow for minor tracking errors, the TG also has a tracking adjust control which allows for minor frequency offsets.