R&S 4200 Series Operating Manual page 67

Configuring with the R&S ZS 4200
TX AM Modulation
Depth
TX Audio ALC
RX Audio AGC
PTT Timeout
PTT Input
Configuration
True Sidetone
Transceiver
5-Carrier Offset
The modulation depth for the AM modulation can be set.
When the automatic level control (see TX Audio ALC parameter) is
activated, the set AM modulation is ensured over a dynamic range of
±15 dB at the TX audio level interface (X5.2/3).
Note: The AM modulation should be left at 90 % all the time, since the
radio link is best at this value.
The automatic level control for the audio modulation can be switched on
and off.
When this function is activated, the set AM modulation depth (see TX AM
Modulation Depth parameter) is ensured over a dynamic range of ±15 dB
at the TX audio level interface (X5.2/3).
Note: If an automatic level control is active in the system external to the
radio, then the level control of the radio should be switched off.
The automatic gain control in the AM demodulator can be switched on and
off. It ensures that the dependency of AF amplitude on modulation depth
signal is compensated. In the range from 30 % to 90 % modulation depth,
the signal (RX Audio) remains constant.
A time limit can be set for the transmit time. This prevents the radio from
transmitting for an unlimited amount of time if the PTT key is pressed
(stuck). With a value of 0 s, the time limit is switched off.
Note: It is recommended to disable the PTT Timeout in the VoIP mode.
There are three different input configurations for the rear PTT input
(connector X5.8/9).
Type I stands for optocoupler input.
Type II should be configured if the system ground (= ground of the PTT
key) does not have the same potential as the rack ground. In this case, the
PTT circuit is fed via the negative voltage of −48 V in the radio.
With the Rohde & Schwarz standard, a pull-up resistor is switched against
the positive voltage of +28 V in the radio.
The built-in receiver demodulates the emitted signal of the transmitter and
a true sidetone is provided to the Audio RX output.
Depending on the configuration, the receiver in the housing is muted
during transmission. In this case, a true sidetone is not supplied.
Note: Not supported in receivers.
The transmitter allows different frequency offsets to be set. Normally the
2-carrier, 3-carrier
−7.5 kHz / −7.3 kHz / −5 kHz / −2.5 kHz / 0 kHz / +2.5 kHz / +5 kHz /
+7.3 kHz / +7.5 kHz are available. In addition, the 5-carrier offset can be
selected; this provides −8 kHz / −4 kHz / +4 kHz / +8 kHz in the
transmitter.
3.15
and 4-carrier offset
R&S XU 4200
with the values of
6166.5368.02.01