Figure 3-1. Spectrum Analyzer Controls, Indicators and Connectors

TM 11-6625-2781-14&P-2

Section III

intensity baseline).

Blanking function also

prevents

blooming

with

variable-

per division absolute voltage amplitude (la) is product

persistence/storage display section.

(blue numerals) of LINEAR SENSITIVITY controls.

21. Adjusts vertical position and gain of trace.

33. Provides 1- and 10-volt, peak-to-peak, 60 Hz

squarewave outputs.

22. Adjusts horizontal position and gain of trace.

CAUTION

These calibrated outputs must never

23. Indicates 1-dB increments for logarithmic

be used with the spectrum analyzer.

amplification; indicates multiplication factors up

(These outputs are for use only with

to unity for linear amplification.

the 1400-series oscilloscope plug-

ins).

24. Selects scan trigger mode.

34. Makes base line parallel with the horizontal

25. Selects logarithmic or linear display mode.

graticule line.

26. Assuming that dB graduation (black numerals)

35. Adjusts brightness of CRT display.

matches position of lighted index lamp, LOG

REF graticule line indicates power level when

CAUTION

LOG/LINEAR (25) is set to LOG. With LOG/

Excessive brightness for a static or

LINEAR set to LINEAR, indicates per division

very slow moving trace may burn the

multiplier for calibrated voltage amplitude for

phosphor and permanently damage

whatever voltage graduation (blue numerals)

the CRT. This caution is applicable

matches position of lighted index lamp.

to both the fixed and variable

persistence/storage CRT; however,

27. Selects scan ramp mode. Ramp is internally

the latter is especially vulnerable to

generated for SINGLE/INT positions but it must

operational errors of this type.

be externally supplied for EXT position. (Refer

to Item 19).

36. Used with FOCUS control (37) to obtain

smallest spot with maximum roundness.

28. Press to initiate scan with SCAN MODE switch

set to SINGLE; press during scan to stop and

reset scan.

37. Focuses CRT beam.

29. Controls SCAN TIME.

38. Lights when line voltage

applied

and

instrument is turned on.

30. May select 100 Hz, 10 kHz or OFF position of

low-pass filter for detected video.

39. Switches line voltage to instrument.

31. Lights for duration of each scan for SINGLE and

40. When used with 1400-series oscilloscope plug-

INT scan modes.

ins, intensifies and returns beam to CRT,

regardless of deflection potentials. When used

with 8550 series plug-ins, the beam finder has

32. Blanks lower part of trace to prevent

no function.

overexposure of photographs (due to high

3-4