Protocol analysis
R&S
®
RTP
765User Manual 1337.9952.02 ─ 12
Frame Start ← Type
For Manchester and NRZ Clocked coding standards, the frame start trigger is set to
the end of the gap time. The start of frame (SOF) condition is the first bit after the gap
(timeout).
For the NRZ Unclocked coding standard, the trigger requires that the signal contains a
start bit. The frame start trigger follows the gap time and is set to the end of the start
bit.
Pattern ← Type
Specifies the pattern match conditions for a payload data check. The trigger is set to
the first occurrence of a matching data bit pattern (which can be freely specified), start-
ing after the minimum gap time, and after the detected start of the data frame. The trig-
ger instant is after the last bit of the specified data pattern.
"Data Pattern"
Specifies the data pattern that is to be found and triggered. The pat-
tern can be entered in binary or hexadecimal format, maximum pat-
tern length is 256 binary characters or 64 hexadecimal characters.
"Bit index oper-
ator"
Sets the operator ("Equal", "Greater or equal", or "In range") to set a
specific bit index (data position).
"Bit index"
Sets the bit index (data position), or the start value of a bit index
range. Default bit index value is 0, permitted values range from 0 to
65535.
"Bit index to"
Sets the end value of a bit index range (data position range). Availa-
ble only, if the "Bit index operator" is set to "In range". Default bit
index end value is 65535, permitted values range from 0 to 65535.
"Word Length"
Sets the number of bits in an NRZ Unclocked word (hence, the size
of the data frame). Default word length is 8 bits, permitted lengths
range from 0 bits to 31 bits .
Note: The NRZ Unclocked coding standard requires a signal that
contains both a start bit and a stop bit:
●
The start bit should be opposite in polarity to the idle state of the
signal, and it is the first transition detected following the gap time.
●
The stop bit should be the same polarity of the idle state, and it is
the last bit in a data frame.
The end of the stop bit and the detection of the next frame's start bit
constitutes the maximum gap time.
In order for the trigger to operate correctly, you have to specify the
correct word length in the trigger menu. The trigger then counts the
number of bits it decodes, and when the count matches the word
length, the next bit is treated as the stop bit.
"Gap Time"
Sets the minimum gap time for synchronization. The trigger is set to a
position after the gap time, when the other trigger conditions are met.
Default gap time is 10 µs, permitted gap times range from 1 ns to 1 s.
"Bit Rate"
Sets the transmission speed for the data signal. Default bit rate is
10 Mbps, permitted bit rates range from 300 bps to 50 Mbps.
Custom: Manchester / NRZ (option R&S RTP-K50)M
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