Protocol analysis
R&S
®
RTP
548User Manual 1337.9952.02 ─ 12
See also: Chapter 13.1.1, "Setup - general settings", on page 512
Source: Tx, Rx
Select the input channels for the transmitter and receiver signals.
Usually, the source is one of the analog channels. Reference and math waveforms are
available as source if the trigger source is one of the analog channels but not the serial
bus.
Do not combine a reference waveform with channel or math waveform because the
time correlation of these waveforms might differ.
Alternatively, digital channels can be used if MSO option R&S RTP-B1 is installed. Dig-
ital and analog channels cannot be used at the same time.
For triggering on a serial bus, analog or digital channel sources are required.
Remote command:
BUS<m>:UART:TX:SOURce on page 1606
BUS<m>:UART:RX:SOURce on page 1605
Threshold
Sets the threshold value for digitization of signals for each line. If the signal value on
the line is higher than the threshold, the signal state is high. Otherwise, the signal state
is considered low if the signal value is below the threshold. The interpretation of HIGH
and LOW is defined by the Polarity.
There are several ways to set the threshold:
●
"Threshold"
Enter the value directly in the field.
●
"Autoset"
Starts software algorithms for determining the signal threshold levels and bitrate.
●
"Find thresholds"
Executes the measurement of reference levels and sets the thresholds to the mid-
dle reference level of the measured amplitude.
Note: If the sources are digital channels, the same threshold values are used for the
parallel and the serial buses. You can set the thresholds either in the parallel bus con-
figuration or in the serial bus configuration.
"Threshold"
Enter the value directly in the field.
"Find thresh-
olds"
Executes the measurement of reference levels and sets the thresh-
olds to the middle reference level of the measured amplitude.
Remote command:
BUS<m>:UART:RX:THReshold on page 1606
BUS<m>:UART:TX:THReshold on page 1606
BUS<m>:UART:TECHnology on page 1607
BUS<m>:SETReflevels on page 1548
BUS<m>:FAUToset on page 1549
Polarity
Defines the logic levels of the bus. The idle state corresponds to a logic 1. the start bit
to a logic 0. "Idle high" (high=1) is used, for example, for control signals, while "Idle
low" (low=1) is defined for data lines (RS-232).
UART/RS-232/RS-422/RS-485 (option R&S
RTP-K2)
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