ADInstruments AD8000 Series Instruction Manual page 58

AD8000 Series Spectrum Analyzer Instruction
Manual
Attention: the signal entering the mixer means the amplitude of the signal
after passing through the attenuator. The amplitude should be less than -10
dBm. For instance, the amplitude of input signal is 0 dBm, the attenuator
should be at least 10 dB, otherwise distortion or damage would happen to
the device.
When the attenuator is set as manual, a '#' mark would appear at the
attenuator parameter display area showing that it is manual currently.
Similarly, when the RBW, VBW and sweep time are changed to manual, a
'#'mark would also appear.
(3) Scale Log/Linear
In 'Log' state, the difference of Y-coordinate is in direct proportion to ΔdB,
while in linear state it is in direct proportion to voltage difference ΔV. In
most cases, the instrument is in logarithm state, but in some special cases
(for example when measuring the modulation degree of AM), the line state
is the better choice.
The common used units in logarithmic state are dBm, dBµV and dBmV. The
conversion could be checked in table 3-1. In log state unit mV could also be
used. The wave will not change with the change of unit.
The common used units in line state are mV, V, µV and nV. The wave will
not change with the change of unit as well.
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Fig. 3-11 Attenuator in Manual Mode