6-42 Table 6-1.—Description of Front Panel Controls, Indicators, and Connectors—Continued ITEM FUNCTION DESCRIPTION 13 CAL When this is activated, the frequency readout can be calibrated to center the center frequency by adjusting the FREQUENCY control for the correct reading. When accomplished, you should deactivate the CAL mode. 14 DEGAUSS When this button is pressed, current through the local oscillator system is reduced to zero in order to minimize magnetism build-up around the LOs. This is done to enhance the center frequency display and amplitude accuracy. You should do this after every significant frequency change and before calibrating the center frequency. 15 IDENTIFY 500 kHz ONLY The signal identify feature can become functional only when the FREQ SPAN/DIV is set to 500 kHz. When activated (button lit), true signals will change in amplitude on every sweep. Images and spurious response signals will shift horizontally or go completely off the CRT display. To ensure that the signal is changing amplitude every sweep, you should decrease the sweep rate so that each sweep can be analyzed. 16 PHASE LOCK When this control is activated (button lit), it will reduce residual FM when narrow spans are selected. In narrow spans, the phase lock can be turned off or back on by pressing the button. Switching the PHASE LOCK off may cause the signal to shift position. In narrow spans, the signal could shift off the display; however, it will usually return to its phase locked position after a few moments. The microcomputer automatically selects PHASE LOCK for a span/division of 50 kHz or below in bands 1 through 3, 100 kHz or below for band 3, and 200 kHz for bands 5 and above. 17 AUTO RESOLUTION This push button, when activated, will automatically select the bandwidth for FREQ SPAN/DIV, TIME/DIV, and VIDEO FILTER. The internal microcomputer selects the bandwidth to maintain a calibrated display. This can be checked by changing the FREQ SPAN/DIV and observing the bandwidth change on the display. This is a continuous detent control that selects the frequency span/div. The span/div currently selected is displayed on the CRT. The range of the span/div selection is dependent on the frequency band selected: BAND     1-3 (0-7.1GHz)   4-5 (5.4-21GHz)     6 (18-26GHz)     7-8 (26-60GHz)     9 (60-90GHz) 10 (90-140GHz) 11 (140-220GHz) NARROW SPAN   10kHz/Div   50 kHz/Div   50 kHz/Div 100 kHz/Div 200 kHz/Div 500 kHz/Div 500 kHz/Div WIDE SPAN 200MHz/Div 500 MHz/Div     1 GHz/Div     2 GHz/Div     2 GHz/Div     5 GHz/Div       10 GHz/Div 18 FREQ SPAN/DIV Two additional bands are provided: full band (max span) and 0 Hz span. When max span is selected, the span displayed is the full band. When zero span is selected, time/div is read out instead of span/div. 19 RESOLUTION BANDWIDTH This is also a continuous detent control that selects the resolution bandwidth. The bandwidth is shown on the CRT display. The range of adjustment is from 1 kHz to 1 MHz in decade steps. When you change the resolution bandwidth with this control, it will deactivate the AUTO RESOLUTION. 20 VERTICAL DISPLAY These four push buttons select the display mode. The scale factor can be seen on the CRT display. 20a 10dB/DIV When this is activated, the dynamic range of the display is calibrated to 80 dB, with each major graticule representing 10 dB.