Output Power Measurement By 1-Tone Signal - Furuno FS-1575 Service Manual

4. Disconnect the output of the AF GEN -2, and then find the "Average power (Pm)"
of TX output from the power meter. Furthermore, read "Peak envelope voltage-2:
E2" on the oscilloscope.
2 tone MOD.
5. Find peak power "Px" from the following equation.
Px = Average power (Pm) × (Peak envelope voltage-1: E1 / Peak envelope
2
voltage-2: E2)
For example, when average 2-tone modulated output power is 100W, peak power to
be obtained doubles to 200W. This is about equal to 1-tone modulated output power
(saturated power).

2. Output power measurement by 1-tone signal

This function determines the TX output power of SSB mode based on TX output power
saturated by increasing input level. Saturated power is recognized as peak power.
Procedure)
1. Set the output frequency of the AF GEN to 1500 Hz.
1500Hz
AF GEN
approx. -36dBm
(600 ohm)
2. Make measurement of TX output power by sequentially increasing input level at a
1500 Hz frequency starting from several 10 percent of nominal input level.
Continue this measurement until the TX output power becomes saturated.
CONFIDENTIAL (internal use only)
This confidential document is used only by FURUNO authorized persons.
It is strictly prohibited to reproduce the document in whole or in part without prior written permission of FURUNO.
1 tone MOD.
E1
Px
FS-2575C FS-xx75T
Fig. 5.1.2 1-Tone Measurement Circuit
5-12
5.1 Overview of Output Power Adjustment
50 ohm
Power
Dummy
meter
Oscilloscope
E2
Pm
Spectrum
analyzer