Rohde & Schwarz CMU-K20, Руководство по эксплуатации

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Adaptive Multi-Rate (AMR) Speech Codec
CMU-K20/K21/K22/K23/K24
1115.6088.12 4.206 E-12
Defining and
testing threshold
values The standard places the following restrictions to the threshold values:
•
The hysteresis must be positive or zero:
Up (j)
≥
Down (j + 1) for j= 1 to 3
•
Up and Down thresholds must be in descending order:
Down 2 ≤ Down 3 ≤ Down 4
Up 1 ≤ Up 2 ≤ Up 3
The C/I is estimated by the MS under test, so the mapping between the
TCH Level
and the thresholds depends on the test setup and on the mobile. As a general rule,
reducing (increasing) the
TCH Level
in the used timeslot by n dB reduces
(increases) the C/I ratio by roughly the same amount.
Remote control
CONFigure:NETWork[:CSWitched]:AMR:HRATe:RSETting
CONFigure:NETWork[:CSWitched]:AMR:FRATe:RSETting
The following two softkeys define the codec modes to be used in both signal directions:
Codec
Mode DL
The
Codec Mode DL
softkey sets the codec mode that the CMU uses to generate
the speech data transmitted to the MS under test. The CMU maintains this mode
during the measurement, irrespective of the DL codec mode requested by the
mobile under test.
The DL codec mode that the MS requests according to the
AMR Rate Set
settings
is indicated to the left of the input field for the DL codec mode.
Note: All Bit Stream settings involving a closed loop or pseudo-random bit
sequences require equal uplink and downlink codec modes. Different
codec modes can be tested with
Bit Stream = Handset
or
Handset
Low.
Remote control
CONFigure:NETWork[:CSWitched]:AMR:HRATe:DLCMode
PROCedure:NETWork[:CSWitched]:AMR:HRATe:DLCMode
CONFigure:NETWork[:CSWitched]:AMR:FRATe:DLCMode
PROCedure:NETWork[:CSWitched]:AMR:FRATe:DLCMode
[SENSe:]MSSinfo:AMR:HRATe:DLCMode?
[SENSe:]MSSinfo:AMR:FRATe:DLCMode?
Codec
Mode UL
The
Codec Mode UL
softkey sets the codec mode that the mobile under test shall
use in uplink direction.
The actual UL codec mode used by the MS is indicated to the left of the input field
for the UL codec mode.
Note: All Bit Stream settings involving a closed loop or pseudo-random bit
sequences require equal uplink and downlink codec modes. Different
codec modes can be tested with
Bit Stream = Handset
or
Handset
Low.
Remote control
CONFigure:NETWork[:CSWitched]:AMR:HRATe:ULCMode
PROCedure:NETWork[:CSWitched]:AMR:HRATe:ULCMode
CONFigure:NETWork[:CSWitched]:AMR:FRATe:ULCMode
PROCedure:NETWork[:CSWitched]:AMR:FRATe:ULCMode
[SENSe:]MSSinfo:AMR:HRATe:ULCMode?
[SENSe:]MSSinfo:AMR:FRATe:ULCMode?
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