TDR Measurement, Fault Detection, Controlled Impedance, & Impedance Calculation

High Frequency  & TDR Measurement Technology & Time Domain Reflectometry - made by Sequid GmbH

Sequid GmbH - Your High Frequency, Controlled Impedance & TDR-Experts

Sequid GmbH is a young and innovative high-tech company focussing on the field of high frequency and controlled impedance measurement technology. We are mainly aiming at making the versatile time domain reflectometry (TDR) applicable to unsolved measurements challenges. Our existing measurement technology is especially well suited for controlled impedance printed circuit boards (PCB), either on test coupons or in-circuit, cables and connectors. We are your competent partner when it comes to affordable high performance TDR measurement equipment, easy & comfortable report creation as well as impedance calculations.

We are mainly focussing on the following applications:

  • High frequency measurement technology (high resolution TDR measurements in the picosecond domain, scattering parameters in GHz frequency domain)
  • Controlled Impedance: controlled impedance PCBs, cable & connectors, wave im­pe­dance measurement, & calculation.
  • Fault detection & localization on printed circuit boards and in electrical & electro-mechanical devices with spatial resolution <10mm
  • Dielectric spectroscopy in the GHz range (complex permittivity measurements)
  • Materials measurement (food industry, moisture measurement, geo­physi­cal applications)
  • Industrial process control (fermentation, complex fuel gauging).
  • Impedance calculations.

TDR & Controlled Impedance Measurement with STDR/T-65 Technology

The wide range of applications of TDR measurement becomes possible by the high precision, temperature stability and EMV immunity of the STDR-65 base technology. Particularly, the time-base jitter within the whole temperature range from 0°C and 40°C (32°F and 104°F) is <500fs, thus even very small changes of the TDR signals can be detected reliably. Due to the robustness (protection class IP55) and the small form factor the STDR-65 is the optimal TDR solution for laboratory & outdoor as well as for industrial applications. With the DTDR-65 Sequid also provides a differential TDR with the same high performance as the STDR-65.

Controlled Impedance & Fault Localization Tools PCBs, Connectors, & Cables

By means of the high precision TDR measurement devices STDR-65 and DTDR-65 (differential) you can easily perform impedance measurements on impedance controlled systems with transmission lines supporting data rates up to 10Gbps. This is valid for printed lines, connectors, and cables. Because of the high flexibility of the TDR devices they can utilized for R&D as well as for production purposes. Furthermore Sequid provides software modules for characterizing base materials for PCBs (e.g. dielectric constant).
A very original application of TDR technology has been the detection and localization of defects in underground & submarine cables. The Sequid TDR devices STDR-65 and DTDR-65 utilize very steep step signals, allowing a high spatial resolution and thus the adoption of the technology from spacious to small systems as for example PCBs or electrical & electromechanical components. Sequid provides all-in-one solutions, which can be due to versatile interfaces easily integrated into your production & testing environment.

STLC - The affordable Transmission Line Impedance Calculator

Sequid provides an affordable online tool for the calculation of PCB transmission line impedances. By means of a powerful field-solver method all frequently used line types can be calculated online. We would be glad to inform you about prices & conditions.

SMAS® - für spezialisierte TDR- & TDT-Systeme

The building block system SMAS is valuable help for professional developers. The high performance clock & pulse generators in the pico­second range with their excellent low jitter performance as well as the programmable frequency divider in the GHz range can easily be combined with existing TDR or other high frequency equipment to speed up your design process. The latest development of the product range is the 8.4GHz frequency counter

Broadband Dielectric Spectroscopy

Sequid has a long lasting expertise in the area of dielectric spectroscopy. Our knowledge and experience have consequently been transferred into practical measurement equipment, namely the high performance open-ended coaxial line probe SDM-10G and an easy to use application software for dielectric measurements. The software can be applied either with the STDR-65 or with other standard vector network analyzers.

RFQ-Scan: Material & Food Analysis

The unique RFQ-Scan® combines a high performance TDR with an open ended coaxial line sensor in an ergonomic chassis. The patented combination of TDR technology and multivariate statistics enables determination of selected material parameters based on complex dielectric properties. This method was developed by Microwave Laboratory of the Christian-Albrechts-University in Kiel, Germany.

Consulting Services in high-frequency measurements & circuit design

In state of the art measurement and entertainment devices as well as in embedded systems, high frequency (HF) circuit design becomes more and more important. If design rules for controlled impedance transmission paths are violated, the proper functioning of the entire systems may be massively corrupted. Sequid's high frequency engineers own many years of expertise and support you to solve complex problems in the areas of circuit design, controlled impedance and high frequency measurement issues.


Sequid - your expert for high frequency, controlled impedance & TDR measurements located in Bremen (Germany) - is closely linked with companies and institutes in many fields of applications. Based on this technology network a company with a corporate culture of innovative skills and flexibility has evolved. This company philosophy is the basis for professional developments of customer orientated solutions - also in cases of highly innovative and even unusual applications.

Benefit from the experience of your controlled impedance & high frequency TDR experts. Working with us offers many advantages:

  • contacts to nameable institutes & companies
  • long lasting expertise in high frequency measurement technologies
  • specilists for controlled impedance design and impedance calculations
  • further development of our products

Contact us directly, we will be glad to inform you about our products & services!