External Modulation; Operational Principle - MOGlabs ARF021 Manual

5. External modulation

WARNING: The modulation inputs are nominally ±1V, and can be permanently
damaged by applying higher voltages. Ensure that modulation is disabled when
disconnecting the back-panel
results. 50Ω termination is recommended when not in use.

5.1 Operational principle

Note: Phase modulation uses the "
The ARF/XRF supports external modulation of the
through the modulation input
Frequency, amplitude and phase modulation of the
and dual-modulation is possible for simultaneous
SMA connectors, as floating inputs can cause unexpected
Modulation is performed by digitising the analogue input signal,
which is then multiplied by the modulation gain and added to the in-
ternal control value associated with the particular modulation mode
("frequency tuning word" for frequency, "amplitude scale factor" for
power or "phase offset word" for phase). Limits are applied to the
value to ensure that the power is always limited to the value set
LIMIT
with the command.
The ADC operates at 62.5 MS/s with 12-bit resolution (±1 V range),
anti-aliased with 7
of 10 MHz. Simultaneous modulation of two parameters is possible,
although one mode will have a reduced bandwidth (see §5.3).
Modulation is enabled/disabled with the
ple, to enable
AM
Modulation is not available in table mode.
FM/PM
SMA connectors on the back-panel.
th
-order filters for a measured 3-dB bandwidth
on channel 1, use the command
"/" FREQ " input
27
RF in NSB
are supported,
RF
FM/AM
MDN
command. For exam-
MDN,1,AMPL,ON
SMA connector.
mode
or .
FM/PM
.