MegiQ VNA04 Series, Руководство пользователя

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VNA0440 – VNA0440e
VNA0460 – VNA0460e
user manual V3.1
- 12 -
www.megiq.com
Sweep generator
The signal generator generates a RF signal that sweeps over a frequency range. This signal
is used for the measurements. The signal can be switched to one of the output ports
P1 or
P2 , for the 'transmitting' part of the measurement.
The VNA04x0e also has a separate Generator Output port. A programmable amplifier
allows setting the desired signal level.
Note: you can not only sweep the generator frequency, but also the output power, e.g. to
characterize complex impedance versus applied power.
I/Q detectors
For the “receiving” part of the measurement, the carrier is fed into the I/Q detectors. Note
that in case of a S11 or S22 measurement the transmit port is the same as the receive port.
There are two receive channels, port 1 and port 2. Each input feeds first into an attenuator
for setting the right signal level to the detectors. The I/Q detectors are used to detect the
real and the imaginary part of the signal with the generator as reference. This information,
converted to digital in the ADC, together with the calibration data, is used to calculate the
complex impedances, scattering parameters, etc.
Controller
The controller, controls all functions and hardware within the instrument, stores
calibration data and processes the raw measurement data. It also communicates over USB
to the PC that holds the user interface software, used to make measurements, display and
store the results.
Bias circuit
The VNA-04x0 e comes with an internal
programmable bias generator that acts like a
regulated V/I power supply. The range is -
12V...+12V and 1...100 mA also both
polarities.
The bias generator can be stepped for
characterizing circuits under different bias
conditions.
The software can set all of the RF ports to
connect to the bias generator, to a low
resistance to ground, or keep open. The
ground resistance provides a return path
(through a diode or other device) for the bias
current. An open port has a resistance of 100kOhm to ground.
18R
100k
P1
18R
100k
GEN
18R
100k
P2
CV/CI
MegiQ VNA04x0e Bias Circuit