R&S M3SR 4100 Series, Руководство по эксплуатации

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Operating Manual 6175.4760.02 – 01 4.137
M3SR Series 4100 Changing the Maximal Message Block Length
4.5.4.4 Changing the Maximal Message Block Length
Softkey Type Description
Editor 1. Press 'MB Length' softkey.
2. Enter desired block length.
3. Press 'ENT' to confirm.
Possible values:
0 to 100
By means of the message block length setting,
the operator can change the maximum
amount of interleaver frames for transmission
and reception.
Once the receiver modem has decoded a sig-
nal with the maximum block length configured
here, the HF Modem returns to acquisition
mode.
To other way round, a transmission is termi-
nated after the transmitter modem has
reached the maximum message block length.
The value 0 reflects an infinite amount of inter-
leaver blocks. In this case the modem will nev-
er return to acquisition as long as a valid
modem signal is decoded.
For transmission this means, that the modem
will never terminate a transmission as long as
enough user data is available.
Operation with a specified number of input
data blocks may be used by an external ARQ
protocol where the size of the ARQ packet is
fixed, or occasionally changed to accommo-
date changing propagation conditions.
The user has to make sure identical mes-
sage block length settings exist within one
network. If changes are needed, the data
protocol above the HF modem has to take
care of this.
In connection with the use of a fixed maximum
message block length, a deactivated message
protocol (EOM) can be used to increase
throughput.
This parameter is adjustable for HF Modem
type STANAG 4539 only.