Rohde & Schwarz CMU-K20, Руководство по эксплуатации

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Signalling: Connection Control
CMU-K20/K21/K22/K23/K24
1115.6088.12 4.182 E-12
The uplink frame trigger signal is also fed to pin 2 of the AUX 3
connector at the front of the instrument where is can be tapped
off to synchronize external devices; see
Output Trigger
below. It
consists of a high-pulse TTL signal with its rising edge at the
beginning of timeslot 0 of each MS TDMA frame except the idle
frames and with a length of exactly 1 timeslot (577
µ
s).
For the
Free Run, RF Power
and
IF Power
settings the input signal must be a burst
signal. Triggering via an external signal is only possible in the
Non Signalling
mode.
In contrast,
Signalling
measurements must be triggered by the signal from the
signalling unit or from the mobile phone.
RF Power
trigger signals have a small dynamic range which may not be sufficient
for triggering. It is recommended to trigger by the
IF Power
instead.
Some measurements require a particular trigger source. E.g., the
Timing Advance
Error
in the
Modulation
menu can be measured with
Signalling
trigger mode only.
Remote control
TRIGger[:SEQuence]:SOURce
SIGNalling | FRUN | RFPower | IFPower
Level
The
Level
section defines the trigger thresholds if the measurement is triggered by
the
RF Power
or
IF Power
(see
Source
function above) respectively. Both
thresholds are defined relative to the maximum input level set in the
Analyzer
tab
(see section
Input Path (Connection Control – Analyzer)
on p. 4.184 ff.). The
Level
settings have no influence on
Free Run
or
External
trigger measurements.
Note: The trigger levels are always relative to the current maximum input
level. If
Max. Level
is set manually
(RF Mode = Manual)
, the current
input level is constant and equal to the setting value. In autoranging
mode
(RF Mode = Auto)
, the current maximum input level is
dynamically adapted to the measured RF input level; the trigger levels
change accordingly.
The
RF Power
trigger threshold is the RF input signal level
(Wideband Power
, see
p. 4.92 ) beyond which the trigger condition is satisfied and a measurement is
initiated.
Low
Low trigger threshold, equal to approx. the
RF Max. Level
–26
dB
Medium
Medium trigger threshold, equal to approx. the
RF Max. Level
–
16 dB
High
High trigger threshold, equal to approx. the
RF Max. Level
–6 dB
The
IF Power
trigger threshold is the IF trigger signal level beyond which the
trigger condition is satisfied and a measurement is initiated. The
IF Power
input
value defines the trigger threshold relative to the maximum input level:
IF power trigger threshold = <RF Max. Level> + <IF Power>
Remote control
TRIGger[:SEQuence]:THReshold:RFPower LOW | MEDium | HIGH
TRIGger[:SEQuence]:THReshold:IFPower <Power>
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