Tektronix XYZs of Oscilloscopes

Specialized probes for current, high voltage, optical probes, etc., converting non electrical signals into electrical signals requires matching the measurement scenario (such as high voltage probes for measuring voltage signals)

(2) Probe accessories and selection

Intelligent interface: Automatically identify probe attenuation (such as 10X) and type, adjust oscilloscope display.

Grounding lead adapter: Shortens the grounding distance from the probe tip to the DUT, improving high-speed signal integrity.

Selection principle: Probe+oscilloscope bandwidth ≥ signal maximum frequency × 5, minimize load (resistance/capacitance/inductance).

Performance Terms and Considerations

(1) Core performance parameters

Parameter definition and key data calculation formula/rule

The bandwidth sine signal attenuates to a frequency of 70.7% (-3dB), which determines the high-frequency response of the signal by 5 times. The rule is: oscilloscope bandwidth ≥ signal highest frequency component × 5

The rise time of the signal from 10% to 90% amplitude reflects the ability to capture rapid changes by 1/5 rule: oscilloscope rise time ≤ fastest rise time of the signal × 1/5; Rise time=k/bandwidth (k=0.35-0.45, 0.35 for<1GHz, 0.40-0.45 for>1GHz)

Sampling rate per second (S/s) determines real-time sampling of waveform details: sinx/x interpolation must be ≥ 2.5 times the highest frequency of the signal; Linear interpolation requires ≥ 10 times the highest frequency of the signal

The waveform capture rate is the number of waveforms captured per second (wfms/s), which determines the transient event capture probability DPO: in the millions per second; DSO: Level 10-5000 per second

Record the number of sampling points for a single waveform to determine the data volume. Time interval=record length/sampling rate, for example: 100k point record length, 1GS/s sampling rate, time interval=100 μ s

The effective number of bits measures the accuracy of ADC reconstruction of sine waves, and the signal frequency and amplitude need to be specified for noise and distortion effects

The ability of a vertical amplifier to amplify weak signals with vertical sensitivity, measured in mV/partition. The minimum voltage for a general-purpose oscilloscope is approximately 1mV/partition

The accuracy of timing displayed by the time base precision level system is usually a percentage error (such as ± 0.01%)

(2) Other considerations

Scalability: Supports increasing memory, application modules (such as jitter analysis, video testing), and third-party software (MATLAB).

Usability: Front panel partition (vertical/horizontal/triggered), graphical interface, touch screen, portability (suitable for laboratory/field).

Oscilloscope Operation&Measurement Techniques

(1) Operation steps

Correct grounding:

Oscilloscope: 3-pin power plug grounded to prevent electric shock and ensure measurement reference.

Personnel: Wear a grounding wristband when in contact with IC to prevent static damage (IC conductive path is fragile).

Control settings:

Vertical: Select the channel, center the voltage/grid and position, couple with DC, and turn off the variable gain.

Horizontal: seconds/grid and centered position, record length can be selected as needed.

Trigger: Set the mode to automatic, select the current channel as the source, center the trigger level, and set the minimum suppression.

Calibration: If the ambient temperature changes by more than 5 ℃ or once a week, perform "signal path compensation" (refer to oscilloscope manual).

Probe connection and compensation:

Connection: Connect the probe tip to the test point and the grounding clip to the DUT ground (such as metal chassis).

Compensation: Connect the probe to the oscilloscope square wave reference signal and adjust the probe to make the square wave edge straight (to avoid measurement errors caused by under/over compensation).

(2) Measurement technology

Voltage measurement:

Adjust the voltage/grid to make the signal occupy 80% of the vertical partition (improve accuracy).

Number signal vertical span (number of partitions), voltage=number of partitions x volts/grid x probe attenuation ratio (e.g. 10X).

Example: 2V/div, signal occupying 4 zones, 10X probe, voltage=4 × 2V × 10=80V (peak to peak).

Time and frequency measurement:

Adjust the seconds/grids to ensure that the signal cycle occupies the full horizontal partition.

The horizontal span of the signal period (number of partitions), period=number of partitions x seconds/grid; Frequency=1/cycle.

Example: 1ms/div, period occupies 5 partitions, period=5 × 1ms=5ms, frequency=1/5ms=200Hz.

Pulse width and rise time measurement:

Pulse width: Measure the horizontal span at 50% amplitude of the signal, multiplied by seconds per grid.

Rise time: Measure the horizontal span at 10% -90% amplitude of the signal, multiplied by seconds per grid.

Phase difference measurement:

Turn on XY mode, CH1 is connected to signal 1 (Y-axis), CH2 is connected to signal 2 (X-axis), forming a Lissajous pattern.

Determine the phase difference based on the shape of the graph (e.g. 1:1 frequency ratio, 0 ° for straight lines, 90 ° for circles).