Spectrum analyzer having enterable offsets and automatic display zoom

Apparatus for use in the spectrum analysis of an input signal, said apparatus comprising:

• input means, having inputs for receiving said input signal and a sampling signal, for providing an intermediate frequency signal in response to said input signal and a sampling signal;
• signal processing means coupled to said input means for providing a first digital signal in response to said intermediate frequency signal;
• memory means coupled to said signal processing means for storing electrical representations of said digital signal in response to a memory control signal;
• memory control means coupled to said memory means for providing said memory control signal;
• display means coupled to said memory means for providing a waveform display of amplitude values over a preselected range of frequency values in response to display control signals and said electrical representations of said digital signal;
• operator controls for providing operator control signals and for providing an offset signal in response to operator manifestations indicating it is desired to include an offset of a preselected display parameter;
• and
• display control means coupled to said memory means, said operator controls and to said display means for providing said display control signals in response to said operator control signals and said offset signal.