Getting Started; Outline Of The Instrument; Schematic Description; Use Of The Instrument - R&S AFQ100A Operating Manual

R&S AFQ100A
2

Getting Started

Outline of the Instrument

Schematic Description

The R&S AFQ I/Q modulation generator forms analog signals to be modulated onto RF carriers by other
instruments. The instrument converts digital baseband signals to analog signals which can be further
processed by an RF generator. The R&S AFQ outputs a two component time dependent analog signal
(vector signal) consisting of an in phase I(t) and a quadrature phase Q(t) signal.
In general, all modulations are possible, yet the R&S AFQ is recommended for vector modulation as
well as amplitude and phase modulation. The instrument performs all vector modulations for which
baseband processing software to be run on a separate control PC is available, e.g. R&S WinIQSIM2 or
Matlab. A control PC takes the payload, e. g. digitized speech recording and calculates the baseband
signals. Therefore, a future radio or mobile communication standard will only require an upgrade of the
baseband processing software.

Use of the Instrument

Common Use
The instrument loads waveforms calculated by simulation software such as Matlab or R&S WinIQSIM2
into its sample memory. After resampling the waveform is D/A converted and output at the I and Q
connectors. The two component analog baseband signal is forwarded to a vector signal generator, such
as R&S SMU. The vector signal generator modulates it onto an RF carrier and transmits the radio
signal to an antenna. Finally, the device under test will receive the radio signal. The received signal can
be checked for transmission errors using the instrument's bit error rate measurement feature.
Remote Control
&
Waveform Calculation
AFQ100A
Sample D/A-
Memory Converter
Bit Error
Measurement
The graphic shows the signal flow from baseband processing, i.e. waveform calculation, to the receiver,
the DUT.
1401.3078.62
Usage of AFQ
Vector
Modulator
I
(SMU)
Q
Clock, Data
2.1
Outline of the Instrument
Device
under
RF
Test
(DUT)
E-3