Spectrum Analyzer Measurement Guide : Spectrum Analyzer Measurements : Adjacent Channel Power
 
Adjacent Channel Power
To select adjacent channel power measurement go to main menu and press MEASURE > MEASUREMENT >ACP. Adjacent Channel Power (ACP) measurements are set up using the SETUP Menu (ACP). Adjacent channel power is a measure of the power that leaks into adjacent transmit channels. The ACP measurement measures the power present in the transmit channel (refer to Channel Power) along with the adjacent transmit channels that have been configured in the SETUP menu.
Adjacent Channel Power Ratio Measurement
1. The status panel provides quick access to common spectrum analyzer settings. See STATUS PANEL (ACP).
2. Green integration bandwidth edge of lower alternate channels.
3. Red integration bandwidth edge of lower adjacent and alternate channels.
4. Blue integration bandwidth edge of lower main and adjacent channels.
5. All ACP measurement parameters are set via the SETUP menu. See SETUP Menu (ACP).
Frequency and span settings for many signal standards can be set as follows:
1. Select MEASURE on the main menu.
2. Select ACP from the MEASUREMENT button.
3. Select SETUP and then do the following:
• Channel spacing
• Main integration bandwidth
• adjacent integration bandwidth
• alternate integration bandwidth
• Limit testing
• Main channel limit
• adjacent channel limit
• alternate channel limit
Adjacent channel power is a constant measurement; after it is turned on, it remains on until a different measurement is selected or the sweep is paused. ACP is calculated at the end of each sweep.
STATUS PANEL (ACP)
Below is the status panel with the corresponding minimized status panel icons for adjacent channel power measurement.
Status Panel with Minimized Status Panel Icons (Adjacent Channel Power)
REF LEVEL
Sets the reference level of the top graticule line in the selected units. If the reference level offset is not zero, OFFSET REF LEVEL is displayed at this location.
SCALE/DIV
Sets the graticule scale/division for log-based units. This setting does not apply to linear units.
REF LEVEL OFFSET
Sets the reference level offset in dB units. This setting can compensate for the presence of external input attenuation or gain.
FREQ OFFSET
Accounts for frequency conversions outside of the analyzer. Refer to Setting Frequency Parameters.
ATTEN LEVEL
When auto attenuation is off, sets input attenuation.
PRE AMP
Toggles the low-noise front-end preamplifier on or off. Refer to Setting Amplitude Parameters.
TRACES/CURSORS
Displays the current status of up to six traces or cursors in a quick-view summary. When the measurement view is set to RF Spectrum, trace information is displayed in this area. When the measurement view is set to Spectrogram, cursor information is displayed in this area. Cursors are available in the Spectrum measurement with the Spectrogram view selected.
The summary information includes the trace or cursor number, type, mode, and detector type. The active trace will show a highlighted background with the mode and detector type restated under the table. In Spectrogram, a reference trace (T0) will show you the settings of the trace used to fill the spectrogram. The reference trace settings are applied to all traces and cursors while in Spectrogram view. Selecting a trace or cursor in the summary panel activates the pressed trace or cursor and opens the TRACE menu, allowing you to select and set up an individual trace or cursor as desired. Refer to Setting Trace Parameters.
SWEEP
Toggles the current sweep setting between continuously or sweep once. Refer to Setting Sweep Parameters.
FREQ REFERENCE
Indicates the current frequency reference source of Internal High Accuracy (used after GPS has lost sync, but while the internal clock still has good GPS reference), Internal Standard Accuracy, External, or GNSS (GPS) Hi Accy (requires GPS). The instrument automatically selects the frequency reference in the following order of priority: external, GPS, then the internal time base.
SETUP Menu (ACP)
The Adjacent Channel Power SETUP menu is available in MEASURE > MEASUREMENT > ACP > SETUP. Once the ACP measurement is selected, the SETUP menu can be quickly accessed by tapping on the summary display area below the spectrum window.
SETUP Menu (ACP)
 
CHANNEL SPACING
Sets the channel frequency spacing (center channel to center channel).
MAIN INTEG BW
Sets the range of integration used in calculating the power within the channel. The integration bandwidth (IBW) is displayed as two vertical dashed lines for each channel.
ADJ INTEG BW
Sets the range of integration bandwidth used in calculating the power in the adjacent channel.
ALT INTEG BW
Sets the range of integration used in calculating the power in the alternate channel.
LIMIT TYPE
Selects Absolute or Relative for the limit evaluation.
LIMITS
Turns on or off the use of ACP limits.
MAIN CH LIMIT
Sets the main channel limit.
ADJ CH LIMIT
Sets the adjacent channel limit.
ALT CH LIMIT
Sets the alternate channel limit.
PRESET SETUP
Sets all ACP setup parameters to default. Turns off limits.