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Grf-1300a user manual and teaching materials, 输入信号, Acpr – GW Instek GRF-1300A User Manual

Page 84

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GRF-1300A 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

输入信号

f

f

B

+

0

0

0

f

B

0

3

f

B

0

3

f

B

+

Figure 7-2.
Definition of
ACPR

0

f

0

f

B

+

0

f

B

0

3

f

B

0

3

f

B

+

p

carrier

ACPR

channel space

adj

p

bandwidth

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