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Spectrum Analyzer 2-14 Channel Power Measurement
Spectrum Analyzer MG PN: 10580-00349 Rev. M 2-19
2-14 Channel Power Measurement
Channel power measurement is one of most common measurements for a radio transmitter.
This test measures the output power, or channel power, of a transmitter over the frequency
range. Out-of-specification power measurements indicate system faults, which can be in the
power amplifiers or in filter circuits. Channel Power measurements can be used to validate
transmitter performance, comply with government regulations, or to keep overall system
interference at a minimum.
Frequency and span settings for many signal standards can be set.
1. Press the
Freq
main menu key.
2. Press the
Signal Standard
submenu key. Choose the desired standard and press
Enter
.
3. Press the
Channel #
submenu key to enter the channel number at which the
measurement is to take place and press
Enter
.
4. Press the
Shift
key then the
Measure
(4) key. Then press the
Power and Bandwidth
submenu key, and press the
Channel Power
submenu key.
5. Press the
On/Off
submenu key to start and stop channel power measurements.
Channel Power Measurement for GSM
Global Systems for Mobile (GSM) communication is a globally accepted standard for digital
cellular communication. A number of frequency bands that are allocated to GSM mobile
phones use a combination of Frequency Division Multiple Access (FDMA) and Time Division
Multiple Access (TDMA). Within each band, are approximately one hundred available carrier
frequencies on 200 kHz spacing (FDMA), and each carrier is broken up into time-slots so as to
support eight separate conversations (TDMA). GSM uses the Gaussian Minimum Shift
Keying (GMSK) modulation method.
Required Equipment
• Test Port extension cable, Anritsu 15NNF50-1.5C
Procedure
1. Using the test port extension cable, connect the signal source to the
RF In
test port.
2. Press the
Amplitude
main menu key and press the
Reference Level
submenu key to set
the reference level to
–20 dBm
. Adjust the values given in this procedure to match your
measurement conditions.
3. Press the
Scale
submenu key and set the scale to
10 dB/div
.
4. Press the
BW
main menu key and verify that
Auto RBW
and
Auto VBW
are
On
.
5. Press the
Freq
main menu key followed by the
Signal Standard
submenu key. Scroll
through the dialog box using the up or down arrow keys or the rotary knob to highlight
the
GSM 900 - Downlink
standard for the measurement and press
Enter
.
6. Press the
Channel#
submenu key and enter the channel number using the keypad, the
arrow keys, or the rotary knob. For this example, select Channel
60
.
7. Press the
Shift
key then the
Measure
(4) key. Then press the
Power and Bandwidth
submenu key, and press the
Channel Power
submenu key.
8. Verify that the center frequency is set to that of the GSM signal, in this case 947.0 MHz
by looking at the center frequency annotation on-screen.