Operation and Examples of Trigger Function

MSA500 series Signal Analyzer offers strong trigger functions on real-time mode.
On this document, the way to operate and some examp les are introduced.

Trigger Source Selection

At first the trigger source described below should be selected when the trigger function is used.

Free Run:	The waveform is updated without any condition.
IF Level	Trigger condition is defined as the ratio between the instantaneous signal level and the full scale of IF signal path. If the signal level exceeds the trigger level, the waveform is updated.
Power	Trigger condition is defined as t he total power within the span. Trigger level is described as the relative value ag ainst the reference level. When the trigger slope is set to "RISE", if the sig nal power exceeds the trigger level, the waveform is updated. When the trigger slope is set to "FALL", if the sign al power is lower than the trigger level, the waveform is updated.
Channel Power	Trigger condition is defined as the total power within the channel. The span is divided into 5 then each piece is defined as the channel. Trigger level is described as the relative value against the reference level. The trigger slope setting works as same as Power trigger.
External	Trigger condition is defined as the external trigger input voltage. When the trigger slope is set to "RISE", if the inp ut level exceeds the fixed threshold (0.56V), the waveform is updated. When the trigger slope is set to "FALL", if the input level is lower than the fixed threshold(0.56V), the waveform is updated.

The comparison table is shown in below. Please refer to the table at section 7 for the sample time.

Trigger Source	Time Resolution	Slope	Level Range
IF Lever	14.7ns	RISE only	1 to 100 %（1% Step）
Power	1sample	RISE/FALL	-40 to 0 dB（1dBStep）
Channel Power	5sample	RISE/FALL	-40 to 0 dB（1dBStep）
External	14.7ns	RISE/FALL	0.56V Fixed

Pre-Trigger Setting

Pre-Trigger defines how many data is captured before the trigger event.

It is available to choose 0/25/50/75/100%.

Trigger Slope Setting

This is the choice of the trigger slope "RISE" or " FALL". Please refer to "1" for the operation.

Scan Setting

This is the choice of the waveform update is one ti me (Single) or repeatable (Continuous).

Trigger Level Setting

IF Level	Set as the ratio against the ful l-scale. 1 to 100% at 1% step.
Power	Set as the relative value against the ref erence level. 0 to –40dB at 1dB step.
Channel Power	Set as the relative value against the reference level. 0 to –40 dB at 1 dB step.

Trigger Channel Setting

Channnel Power	Choice of the one of 5 channels to be used as the trigger source. 1 is the lowest frequency, 3 is the center and 5 is the highest frequency.

Acquisition Frame Setting

It sets the acquisition length as the frame count.

The setting menu is available with pressing "OPERATION MODE" button.

Press "ACQ FRAME" (F3) then set the frame count by the encoder.

"ENC STEP"(F6) offers the step size setting of the encoder.

1frame consists of 1024 sample on time domain.

Sample/Frame time and maximum acquisition time depe nds on the span setting as follows.

Span	Sample Time	Frame Time	Maximum Acquisition Time
20MHz	29.4ns	30.1us	0.4935s
10MHz	58.8ns	60.2us	0.9869s
5MHz	118ns	121us	1.973s
2MHz	294ns	301us	4.935s
1MHz	588ns	602us	9.869s
500kHz	1.18us	1.21ms	19.73s
200kHz	2.94us	3.01ms	49.35s
100kHz	5.88us	6.02ms	98.69s
50kHz	11.8us	12.1ms	197.3s
20kHz	29.4us	30.1ms	493.5s

Main Analysis Setting

Main Analysis can be set on the menu of "ANALYSIS M AIN"(F1) under "OPERATION MODE" key.

Spectrum	Spectrum Analysis is set. Analysis frame count is fixed to 1.
Spectrogram	Spectrogram Analysis is set.
Overwrite	Overwrite Analysis is set. Trigger source is fi xed to Free Run.
Time Domain	Time Domain Analysis is set. Further selection is sh own in below. Power vs. Time:Y axis is set to Power [dBm] Phase vs. Time:Y axis is set to Phase [degree] Frequency vs. Time: Y axis is set to Frequency [Hz] IQ vs. Time: Y axis is set to I/Q voltage [V] Q vs. I: Y axis is set to Q voltage and X axis is set to I voltage. It is polar display.

Sub Analysis Setting

Sub Analysis can be set on the menu of "ANALYSIS SUB" (F2) under "OPERATION MODE" key.

Power vs. Time: Y axis is set to Power [dBm]
Spectrogram: Spectrogram Analysis is set.
Off:Sub Analysis is disabled.

Start of Acquisition

Press "HOLD/RUN" to start. Press "HOLD/RUN" again to stop.

Example

Intermittent Spectrum Capturing
At this example, MSA500 captures the intermittent signal generated by the transmitter

[Setting Procedure]
1. On Real-time mode, Center Frequency, Span and Reference Level is set as desired.
2. Press "TRIG" - "TRIG SRC SELECT" [F1] - "IF LEVEL" [F4] then set IF LEVEL to 5%
3. Press "RETURN"[F6] – "SCAN"[F4] then set to "CONTINUE "
4. Press "OPERATION MODE" – "ANALYSIS MAIN"[F1] then select "SPECTRUM
5. Press "RETURN"[F6] – "ANALYSIS SUB"[F2] then select "OFF"[F3]
6. Press "CALC" – "MAX HOLD"[F2] the set hold count to " **"
7. Press "HOLD/RUN" to start acquisition
8. When the signal is captured, Press "HOLD/RUN" to stop the acquisition
ASK signal analysis generated by ETC road side unit
We analyze ASK signal with split phase coding on this example.

[Setting Procedure]
1. On Real-time mode, Center Frequency, Span and Refere nce Level is set as desired.
2. Press "TRIG" - "TRIG SRC SELECT"[F1] - "POWER"[F2] then set POWER to -35dB
3. Press "RETURN"[F6] – "SLOPE"[F3] RISE, "SCAN"[F4] then set to "SINGLE"
4. Press "OPERATION MODE" – "ANALYSIS MAIN"[F1] - "T DOM AIN"[F4] – "POWER-T"[F1]
5. Press "RETURN"[F6] – "ANALYSIS SUB"[F2] - "SPECTROGM" [F2]
6. Press "RETURN"[F6] – "ACQ FRAME"[F3] then set to 500
7. Press "HOLD/RUN" to start acquisition
8. When acquisition is completed, adjust "STT FRAME"[F4], and "ANL FRAME"[F5] to set the analysis window for Main analysis.
Transmit time measurement of Smartmeter signal
We measure the transmit time of the GFSK signal generated by Smartmeter.
By the measurement below,
- Frame time:301[us] @2M span
- Transmit Frame count:754
- Transmit Time:0.301 x 754 = 226.9 [ms]
[Setting Procedure]
1. On Real-time mode, Center Frequency, Span and Refere nce Level is set as desired.
2. Press "TRIG" - "TRIG SRC SELECT"[F1] - "POWER"[F2] then set POWER to -35dB
3. Press "RETURN"[F6] – "PRE TRIG"[F2] 0% , "SLOPE"[F3] "RIS E", "SCAN"[F4] to "SINGLE"
4. Press "OPERATION MODE" – "ANALYSIS MAIN"[F1] - "T DOM AIN"[F4] – "POWER-T"[F1]
5. Press "RETURN"[F6] – "ANALYSIS SUB"[F2] - "SPECTROGM" [F2]
6. Press "RETURN"[F6] – "ACQ FRAME"[F3] then set to 2000
7. Press "HOLD/RUN" to start acquisition
8. When acquisition is completed, adjust "STT FRAME"[F4], and "ANL FRAME"[F5] to set the analysis window for Main analysis.