SME Digital Modulation
1038.6002.02 2.117 E-13
- Bit Error Rate Test
The SME is able to switch a receiver to the test mode for bit error rate tests and then send
standard test patterns.
To this end, set a character to “B“ (for BER message) in FRAME CONTENTS. Furthermore, set
any number of continuous frames to “F“ (for filler pattern). In the BER frame, the SME sends the
command for switching over to the BER test mode to the receiver. The FPAT frames contain the
test pattern.
The command in the BER frame contains start and number of test pattern frames. For calculating
the command, the SME searches for the first “F“ in FRAME CONTENTS and sets the length to the
number of continuous FPAT frames.
The calculation of the BER frame is performed when switching on ReFLEX25 and executing
RECALCULATE. This is why FRAME CONTENTS either must be set before switching on
ReFLEX2 or RECALCULATE must be executed.
- Reading Out, Modifying, Returning of Telegram Parts
It is possible to modify parts of the telegram generated by the SME using a host processor and to
have the modified telegram sent by the SME. Likewise, telegram parts generated on the host
processor can be transferred into the custom frames of the SME.
When ReFLEX25 is switched on, the telegram to be sent is calculated and stored in the extension
memory of the SME („XMEM“). The custom frames are
not
changed. For reasons of space, the
individual fragments of the telegram are calculated and filed. During the execution, a so-called
sequencer makes sure that the individual fragments are read such that a valid and complete
telegram is obtained. The sequencer automatically places a sync1 portion, a frame info word and a
sync2 portion ahead of all frames except for the types OTH, RSYN and CUS1 to CUS9.
The individual fragments are stored in the XMEM as follows:
Fragment „start“ „length“
Sync 1 portion 3 224
1920 Frame info words (Ft
1
Ft
0
= 10) 301 1920 * 64
1920 Frame info words (Ft
1
Ft
0
= 11) 125001 1920 * 64
1920 Frame info words (Ft
1
Ft
0
= 00) 250001 1920 * 64
Sync 2 portion 375001 1920 * 80
OTH frame 376001 6000
RSYN frame 383001 5632
IDLE frame 390001 5632
TONE frame 397001 5632
NUM frame 404001 5632
ALPH frame 411001 5632
SCI frame 418001 5632
BER frame 425001 5632
FPAT frame 432001 5632
CUS1 frame 510001 6000
CUS2 frame 520001 6000
CUS3 frame 530001 6000
CUS4 frame 540001 6000
CUS5 frame 550001 6000
CUS6 frame 560001 6000
CUS7 frame 570001 6000
CUS8 frame 580001 6000
CUS9 frame 590001 6000
Separate frame info words are stored for each combination of frame number (0...127) and cycle
number (0...14), accounting for the number 128*15 = 1920 of the frame info words per category.
To Next Page
Loading...
