Absorbing Clamps


MDS 21 C - Absorbing Clamp


  • MDS 21 C-Absorbing Clamp
  • MDS 21 C-Absorbing Clamp_


The Absorbing Clamp MDS 21 C was designed to measure the disturbance power according to CISPR 16-2-2 in the frequency range 30-1000 MHz, it complies to the technical requirements of CISPR 16-1-3. The measurement of disturbance power was introduced in 1969 to the CISPR standardisation. Many fundamental investigations about the clamp construction and the disturbance measurement method itself have been done by the swiss PTT under the leadership of J. Meyer de Stadelhofen, whose initials are still visible in the name of the clamp.


The absorbing clamps basically consists of four functional units:


• RF-current transformer to pick up the measurand. Its position is marked with “CRP” (clamp reference point), which must face towards the EuT

• Absorber chain composed of split, precision grinded ferrite rings to provide a defined RF-termination to the EuT’s line under test and to decouple the mains influence

• Sheath wave supressors to improve reproducability (not visible, located in the lower housing)

• Plastic housing, convenient to open with wheels in roller bearings for easy movement



The use of an external 6 dB attenuator is recommended to improve the impedance matching to the 50 Ω system. In conjunction with a right angle adapter the coaxial cable can be guided perpendicular to the clamp body.


The MDS 21 C complies to all requirements of CISPR 16-1-3 and will be delivered including an individual calibration of the clamp factor CF.

Nominal Frequency Range:  30 ... 1000 MHz
Nominal Impedance:  50 Ω
Insertion Loss (nominal):  17 dB
Decoupling DR:  >21 dB
Decoupling DF:  >30 dB
Max. Current:  30 A
Max. RF-Input Power:

 20 W

Max. Cable Diameter:  17 mm
Connector:  N-female
Length x Width x Height:  645 x 66 (110) x 102 mm
Track:  58 mm
Ground Clearance:  8 mm
Wheel Width:  7 mm
Weight:  5.8 kg
Optional Accessories:

 6 dB N-Attenuator DGA 9552 N
 Angle Adapter N-f N-m
 Coaxial Cable RG 223/U (5 m)


pdficon small Datasheet MDS 21 C




CMAD 1614 - Common Mode Absorption Device


  • CMAD1614
  • CMAD1614_

The CMAD 1614 - Common Mode Absorption Device consists of many precision cut ferrite half-toroids, which are embedded in a grey plastic housing. The unique floating toroid bearing ensures a perfect fit of the ferrite surfaces. Two quick-locks at the long side allow opening and closing of the clamp within seconds. Cable bundles or coaxial cables with a maximum diameter of 26 mm are accepted by the clamp without disassembling connectors or interrupting any circuitry. The combination of short length and large cable hole diameter offer a broad variety of applications for the CMAD 1614. Each common mode absorption device comes with an individually measured calibration certificate.


The CMAD 1614 can be used for both, coaxial cables and unshielded cable bundles, in order to suppress unwanted common mode currents (also called braid currents). Since these unwanted common mode currents are very often a reason for poor repeatability of measurements, the new CISPR 16-1-4 standard recommends the use of absorbing clamps.


Frequency Range: 30 MHz - 200 MHz
Specified in: CISPR 16-1-4
Usable Frequency Range: 10 MHz - 1 GHz
S11 (30 MHz): 0.6 - 0.75
S11 (200 MHz): 0.4 - 0.55
S21: < 0.25
Max. Cable Diameter: 26 mm
Housing Material: PVC
Housing Dimensions: 66 x 70 x 414 mm
Weight: 3.2 kg


pdficon small Datasheet CMAD 1614



CAL CMAD 1614 - Calibration Fixture for CMAD 1614



  • cal_cmad

The CAL CMAD 1614 calibration fixture is used to calibrate / verify the performance of the common mode absorption device CMAD 1614. The fixture consists of an aluminium base plate with two sideplates, adjustable in height and position and each of them equipped with N-connector and inner conductor fixture. A variety of inner conductors with 4 mm diameter is part of the delivery. The calibration fixture was designed for measurements acc. to CISPR 16-1-4 sections 9.5 and 9.6.


Frequency Range: 30 MHz - 200 MHz
Specified in: CISPR 16-1-4
Useable Frequency Range: 10 MHz - 1 GHz
Material: Aluminium
Dimensions: 113 x 150 x 788 mm
Weight: 2.2 kg


pdficon small Datasheet CAL CMAD 1614