Communication Concepts AN758 - Manual (Page 12)

AR
C
HIVE INF
O
RMA
TI
O
N
PRODUCT TRANSFERRED T
O
M/A
–
COM
AN758
12 RF Application Reports
AUDIO
GENERAĆ
TOR
HPĆ201C
WIDEBAND
ENGINEERING
A73D
POWER METER
HPĆ432A
8443A TRACK GENERATOR
8552A IF SECT.
8553A RF SECT.
141T DISPLAY
TEKTRONIX
585
OSCILLOSCOPE
AMPLIFIER
UNDER
TEST
POWER METER
HPĆ432A
POWER METER
HPĆ434A
- 20 dB
- 30 dB
2 kW
50 Ω
TERMIĆ
NATION
POWER
SUPPLY
60 V/40 A
- 10 dB
POWER METER
HPĆ432A
- 6 dB
100 W
MODIFIED
DRAKE
TĆ4XB
- 20 dB
HP SPECTRUM ANALYZER
Figure 16. For two tone operation, a signal from an external audio oscillator is added to a signal from the T-4XB
built-in oscillator, which has been adjusted to 800 Hz.
During single tone testing, the external oscillator (1200 Hz) is switched off . A calorimeter wattmeter in the output can
be used to calibrate the HP-432A’s at frequencies below [ 10 MHz, where their response roll-off begins.
η
(%)
60
50
40
40
30
20
V
CC
= 50 V
η
DRIVER AND POWER
AMPLIFIER P
out
= 1 kW CW
POWER DRIVER,
50 W CW OUT
VSWR
INPUT
VSWR
3
2
1
3
2
1
POWER AMPLIFIER,
P
out
= 1 kW CW
η
VSWR
30 20 15 10 1.5 2.0 3.0 5.0 7.0
Figure 17. VSWR and Efficiency versus Frequency
V
CC
= 50 V
2 MHz
30 MHz
1200 1000 800 600 400 200 0
IM DIST
OR
TION, d (dB)
3
- 20
- 30
- 40
Figure 18. IMD versus Power Output
Figure 19. Photo of Spectrum Analyzer Display
Showing the IMD Products to the 9th Order. Power
Output = 1 kW at 30 MHz (50 V).
IM DIST
OR
TION (dB)
- 25
- 35
- 45
FREQUENCY (MHz)
30 20 15 10 1.5 2.0 3.0 5.0 7.0
1000 W PEP,
50 V
d
3
d
3
d
5
800 W PEP,
40 V
Figure 20. IMD versus Frequency