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Transceiver IMD measurements OH7SV 2004-08-20
Fig 1. The 3rd
order IMD measurements results
-
3rd order dynamic
range 100 dB
-
IP3 +33 dBm
Notes:
The 3rd IMD was measured
with three different frequency combinations with equal results. With 20
kHz frequncy spacing the noise floor was distorted by the noise of generators.
All measurements were made in 80 m band with the following frequecies:
- RX 3.700 MHz, Genetrator
1 3.720 MHz, Generator 2 3.740 MHz
- RX 3.700 MHz, Genetrator
1 3.740 MHz, Generator 2 3.780 MHz
- RX 3.500 MHz, Genetrator
1 3.600 MHz, Generator 2 3.700 MHz
The IP3 was independent
of the gain of AF preamplifier. This amplifier is after the mixer muxer
sampling capacitors. Gains of 29 dB and 39 dB were tested.
Fig 2. Measurement setup
Two HP
E4420B signal generators were used. Wilkinson
splitter is home made with 11 dB loss and better than 30 dB isolation.
Fig 3. Equpiment setup