Built-in-Test (BIT) Jammers Phase Locked Loops Low Cost Modulation Option

EMF Series Comb Generators 95 use a Step Recovery Diode (SRD) to generate very narrow voltage spikes; these in turn produce an output frequency spectrum rich in harmonics. The spacing between the signals is equal to the source that drives the SRD which in most cases is a stable crystal oscillator. Examples of the spectrum for a number of comb generators are included at the bottom of this page. The crystal oscillator is normally internal; however, an external signal can be used to drive the SRD. If only certain combline signals are required for a particular application, a filter tuned to the desired combline must be used. Comb generators have a number of applications. They are often used as Built-in-Test (BIT) oscillators to calibrate receivers; other uses are in Phase Locked Loops (PLL), Jammers, Antenna Testing, Linearizing Voltage Controlled Oscillators, etc.