Setting the Adjacent Channel Power Format

---

When performing an adjacent channel power measurement, several measurement settings must be specified. The measurement settings include bandwidth and measurement time for the center channel. In addition, the measurement settings for the adjacent channels are:

• number of adjacent channels
• offset of the first adjacent channel from the center channel
• offset of the adjacent channels from each other
• measurement bandwidth and measurement time for each adjacent channel

These settings determine how the DSP measures the center channel and its adjacent channels. Depending on the modulation type of the signal you are trying to measure (CDMA, GSM, and so forth), different measurement bandwidths, times, and offsets are required.
Default adjacent channel power measurement settings, called ACP formats, are provided in the E7495A/B base station test sets. Generally, the ACP format is determined by the channel standard you select. However, to accommodate your particular situation, you can decouple the default formats from the channel standard, or you can change each measurement setting independently. The three methods of selecting your measurement settings are:

• Channel: Each channel standard has an associated ACP format. With this method, the optimum measurement bandwidth and measurement time for the modulation type are automatically selected when you set the channel standard. For example, when you select GSM-950 as the channel standard, with this method the test set selects the bandwidth and time and adjacent channel offsets for the GSM format.
• List: Select the ACP format from a list of values that are set automatically-independent of the channel standard.
• Custom: Manually set all parameters: the measurement bandwidth and measurement time for the center and adjacent channel(s), the offset from the center channel for the first adjacent channel, and the offset between adjacent channels.

To Select the Channel Format Type:

	Step	Notes
1.	[ACP Format]
2.	[Format Type]	Each time you press this softkey, the selected option changes. The option you select determines which buttons on the right are active.
3.	[Chan]
4.	Select the standard you want. a. [Chan Std] b. Select the standard using the up and down arrow buttons. c. [Select]	Channel BW/Time is available, but all buttons are grayed out, enabling you only to view the settings. To change any of the settings, choose Cust.

To Select the List Format Type:

	Step	Notes
1.	[ACP Format]
2.	[Format Type]	Each time you press this softkey, the selected option changes. The option you select determines which buttons on the right are active.
3.	[List]
4.	Select the format you want. a. [Format List] b. Select the standard using the up and down arrow buttons. c. [Select]	Channel BW/Time is available, but all buttons are grayed out, enabling you only to view the settings. To change any of the settings, choose Cust.

To Select the Custom Format Type:

	Step	Notes
1	[ACP Format]
2	[Format Type]	Each time you press this softkey, the selected option changes. The option you select determines which buttons on the right are active.
3	[Cust]
4	Set the carrier and adjacent channel bandwidth. a. [Channel BW/Time] b. [Center Chan Meas BW] c. Enter the center channel bandwidth on the numeric keypad. d. [GHz] or [MHz] or [kHz] or [Hz] e. [Center Chan Meas Time] f. Enter the center channel measurement time on the numeric keypad. g. [ms] h. [Adj Chan Meas BW] i. Enter the adjacent channel bandwidth on the keypad. j. [GHz] or [MHz] or [kHz] or [Hz] k. [Adj Chan Meas Time] l. Enter the adjacent channel measurement time on the keypad. m. [ms]
5	Enable the frequency error function from the BW/Time menu. a. On [Freq Err] select On. Each time you press this softkey, the Frequency Error state (On or Off) changes. b. [Back]	When Frequency Error is switched On, the Frequency Error result is added to the metrics display at the bottom of the screen.
6	Set the offset from the carrier to the first adjacent channel. a. [Ctr to Adj Step Size] b. Enter the offset on the numeric keypad. c. [GHz] or [MHz] or [kHz] or [Hz]
7	Set the offset between adjacent channels. a. [Adj to Adj Step Size] b. Enter the offset on the numeric keypad. c. [GHz] or [MHz] or [kHz] or [Hz]
8	Set the number of adjacent channels (from 0-3). a. Enter the number on the numeric keypad. b. [Enter]