Table of Contents
Advertisement
The following factors should also be considered
when choosing your system:
• The 85310A distributed frequency converter
(85301B system) allows the test mixer to be
located at the AUT, avoiding the degradation in
measurement sensitivity due to cable insertion
loss between the 8511A/B RF inputs and the
AUT.
• Measurement sensitivity and acquisition time
are directly related. If averaging is used to
achieve the required measurement sensitivity,
data acquisition times will be increased.
Averaging will improve sensitivity by 10*log
(Averaging Factor) until limited by channel-to-
channel isolation. The increase in acquisition
time can be determined by multiplying the aver-
aging factor by 200 microseconds. If acquisition
time is critical, fundamental mixing using the
85310A will reduce or eliminate the need for
averaging.
• If the distance between the 8530A and the AUT
is large, both the LO source and the 85310A
frequency converter can be remoted from the
8530A. Remote distances of up to 25 meters
cause no degradation in system sensitivity;
beyond 25 meters, the system sensitivity
degrades by 0.1 dB per meter.
The 85301C antenna measurement system utilizes
an 8511A/B frequency downconverter which uses
a harmonic sampling technique with a built-in
voltage-tuned oscillator. This type of downconver-
sion does not require a second synthesized source
as a local oscillator, so it will be a lower-cost RF
system.
The 85301C system has a low-frequency limit of
45 MHz; the 85301B has a low-frequency limit of
100 MHz.
The 85301B system utilizes mixers for frequency
downconversion. While these mixers are relatively
broadband, they are banded. Mixers are available
for the frequency bands of 100 MHz to 3 GHz, 1 to
26.5 GHz, 2 to 50 GHz, 40 to 60 GHz, 50 to 75 GHz,
and 75 to 110 GHz.
The 85301C system provides broadband frequency
downconversion: either 45 MHz to 26.5 GHz, or
45 MHz to 50 GHz coverage.
9
Advertisement
Table of Contents
