SG-2000 MANUAL
134
The SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
©1995, SGC, Inc.
TEL: (206) 746-6310 FAX: (206) 746-6384
21.19
Modulation Characteristics, Peak Envelope Power
Limiting
In order to test the modulation characteristics, a two-tone audio signal was
applied to the microphone input of the transceiver. Frequencies of the tones
were 400 Hz and 1800 Hz. Amplitude of the composite audio signal was
adjusted to ± 10 dB above the level required for full power output (
150 watt
PEP
). The relative level of the two audio tones was set such that the two
principal RF frequency components of the RF output were equal in
magnitude.
The ALC control; R162 - shown in drawing
(Schematic J30100500 2/2)
was
adjusted to limit the power output to 150 watts.
Note that the modulation limiting circuit includes a peak detector thereby
performing the identical function for A3A, A3J and A3H modulation.