User`s guide

Adjacent Channel Power Ratio (ACP)
The leakage of a transmitter into adjacent channels can be measured quickly and easily.
Enter the channel spacing and channel bandwidth, and activate the adjacent channel power
measurement. The spectrum analyzer computes and displays the ACP ratio of both the lower
and upper adjacent channels, marking the higher of the two. The absolute carrier power is read
out and vertical lines on the display mark the channel bandwidth edges.
Selecting ACPGRAPH ON OFF (ON) computes a graph showing the adjacent channel power ratio
for the selected channel as a function of channel spacing, and disables the numerical adjacent
channel power display.
Normally, the spectrum analyzer measurement parameters are set automatically. Parameter
setting can be changed from automatic to manual control using PARAM AUTO MAN . The
following conditions must be maintained to make a valid rms measurement. If these conditions
are not met, errors of up to -2.5 dB can occur for noise-like signals.
n Video bandwidth is at least 10 times the resolution bandwidth.
1 Detector mode is sample (SP). (You can use DETECTOR PK SP NG to change the detector
mode.)
n Resolution bandwidth is less than or equal to 100 kHz.
n Video averaging is OFF.
n Neither MAX HOLD nor MIN HOLD trace mode is selected.
A wider dynamic range is available using the ADJ CHAN POWER extd function. This extended
range is measured by taking two different sweeps with different reference levels and
combining the trace data. The results are displayed in a 13 dB per division format. The
extended ACP function does not provide a continuous measurement mode.
Example: Measure the adjacent channel power of a signal.
1. Connect a signal to the spectrum analyzer INPUT 500.
2. Press [FREQUENCY) and enter the frequency of your input signal to place the signal at the
spectrum-analyzer center frequency.
3. Press [AMPLITUDEI] and adjust the reference level to bring the signal near the top of the
display.
4. Press (MEAS/USER] and Power Menu to access the power measurement functions.
5. Press Setup and CHANNEL BANDWDTH . Enter the value for the channel bandwidth.
6. Press CHANNEL SPACING. Enter the value for the channel spacing. (The spectrum analyzer
will use the last entered values for channel bandwidth and spacing, if they are not
entered.)
‘7. Press Previous Menu to return to the main power menu.
8. Press ADJ CHAN POWER to activate the function.
Making Measurements 4-45