Quick Answer
Oscilloscope calibration at Prism verifies: (1) DC gain accuracy at 5 voltage ranges using a calibrated DC voltage source, (2) bandwidth at –3 dB point using a sine wave source swept from DC to rated bandwidth, (3) timebase accuracy using a calibrated frequency reference, and (4) trigger level accuracy.
Key Takeaways
- Oscilloscope calibration covers DC gain, bandwidth (–3 dB), rise time, and timebase accuracy.
- Reference: Fluke 5720A multi-function calibrator (DC/AC voltage source) + Keysight 53230A frequency counter.
- Bandwidth verification requires a flatness reference from 10 MHz to rated bandwidth (1 GHz+).
- Annual calibration is standard; critical test instruments in R&D labs should be calibrated every 6 months.
- Prism calibrates Tektronix, Keysight, Rigol, Siglent, GW Instek oscilloscopes.
Oscilloscope Calibration Parameters
| Parameter | Method | Typical Accuracy Requirement |
|---|---|---|
| DC Gain Accuracy | Precision DC voltage source at 5 ranges | ±2% of full scale |
| Bandwidth (–3 dB) | Sine wave sweep from 10 MHz to rated BW | ±10% of rated bandwidth |
| Rise Time | Calculated from bandwidth: tr = 0.35/BW | Consistent with bandwidth |
| Timebase Accuracy | Calibrated frequency reference (OCXO) | ±20 ppm typical |
| Trigger Level Accuracy | DC offset voltage at trigger level settings | ±5% of full scale |
| Input Impedance | 1 MΩ // 20 pF and 50 Ω verified | Per specification |
Oscilloscope Brands Calibrated at Prism
- Tektronix (TDS2000, TBS1000, MDO3000, MSO series)
- Keysight / Agilent (DSO-X, MSOX, InfiniiVision series)
- Rohde & Schwarz (RTM, RTA, RTB series)
- LeCroy (WaveSurfer, WavePro, WaveRunner)
- Rigol (DS1000, DS2000, MSO5000 series)
- Siglent (SDS1000, SDS2000X, SDS5000X)
- GW Instek (GDS-2000A, GDS-3000A)
Frequently Asked Questions
What is bandwidth verification in oscilloscope calibration?
Bandwidth (–3 dB) is the frequency at which the oscilloscope's vertical deflection drops to 70.7% of its low-frequency value (–3 dB). Prism verifies bandwidth by applying a calibrated sine wave swept from 10 MHz up to the rated bandwidth and observing where the amplitude drops by 3 dB.
Does Prism calibrate high-bandwidth oscilloscopes (1 GHz+)?
Prism calibrates oscilloscopes up to 600 MHz bandwidth using available reference signal sources. For bandwidths above 600 MHz, calibration is coordinated with specialised high-frequency test facilities.
How often should oscilloscopes be calibrated?
Annual calibration is the standard for most test and measurement departments. R&D labs and calibration labs that use oscilloscopes as reference instruments should calibrate every 6 months.
What is the probe effect on oscilloscope calibration?
Oscilloscope probes (10:1 passive, active differential) affect the overall measurement accuracy. Probe calibration (compensation adjustment) must be checked before use. Full probe characterisation (bandwidth, input capacitance) can be provided as part of the oscilloscope calibration service.
Does Prism calibrate digital phosphor oscilloscopes (DPO) and mixed-signal oscilloscopes (MSO)?
Yes. The calibration parameters are the same for analog, DPO, and MSO channels. Logic analyser channels on MSOs are not within Prism's NABL scope but analog channel performance is fully calibrated.
Written by
Er. Parthiv Kinariwala
Managing Director · Prism Calibration Centre · NABL CC-2480 · Ahmedabad
Er. Parthiv Kinariwala founded Prism Calibration Centre in 2004 and has over 20 years of hands-on experience in calibration engineering, NABL accreditation, and industrial compliance. His team performs 10,000+ calibrations annually from the Vatva GIDC laboratory, serving 5000+ industries across Gujarat.
Prism Calibration Centre — Vatva GIDC, Ahmedabad
Prism Calibration Centre
F-101, Rudraksh Complex 2, Phase 3, GIDC Vatva, Near Jasoda Nagar Cross Road, Ahmedabad — 382445, Gujarat, India
Phone: +91 98245 26444
Email: info@prismcalibration.com
NABL: CC-2480 · ISO/IEC 17025:2017
Hours: Mon–Sat, 9:00 AM – 7:00 PM