GW Instek GRF-1300, User Manual

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GRF-1300 User Manual and Teaching Materials
Experiment
principles
1. ACPR Measurement
ACPR (Adjacent Channel Power Ratio) is the ratio of the
amount of power leaked to an adjacent channel from the main
channel. It represents how much
power from the transmitter leaks into the transmission band of
other channels. The adjacent channel usually refers to the closest
adjacent channels near the transmission channel, other channels
can also be selected, depending on the measurement
requirements.
When two signals with similar frequencies are
input into an RF power amplifier, there are not only two output
signals, but also the inter-modulation signals (input signal 1 ±
input signal 2). A typical input and output frequency
spectrum is shown in Figure 7-1.
Figure 7-1.
RF power
amplifier input
and output
0
f
0
f B
+
0
f B
− 0
3 f B
−
0
3 f B
+
输入信号
Figure 7-2.
Definition of
ACPR
0
f
0
f B
+
0
f B
−
0
3 f B
−
0
3 f B
+
carrier
p
adj
p
ACPR
channel space
bandwidth
80