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Alpha-A Modular Dielectric/Impedance Measurement System


The Alpha-A mainframe is the master unit of the Alpha-A modular measurement system for electric frequency domain measurements.

For dielectric, conductivity and impedance spectroscopy the mainframe has to be operated in combination with one or more test interfaces.

Alpha system

The mainframe contains a frequency response analyzer with a sine wave and dc-bias generator and two ac voltage input channels.

In addition, the mainframe contains the power supplies, analog and digital control lines and the firmware for operation of the test interfaces.

After power on, the mainframe automatically detects the connected test interface and adjust the system functionality to it.

All system functions of the mainframe and a connected test interfaces are controlled by the mainframe IEEE488 GPIB interface port by high level GPIB commands via an external host computer as shown below.

Without a test interface, the mainframe can perform two channel frequency response or gain phase measurements.

Alpha-A Mainframe Types

The following mainframe types with different frequency ranges are available.

Alpha mainframe types Type Code
Upper frequency limit 40 MHz Alpha-AT

Upper frequency limit 20 MHz


Upper frequency limit 3 MHz


Upper frequency limit 0.3 MHz



If operated in combination with a test interface, the available frequency range may be reduced by the test interface frequency range. Impedance measurements up to 40 MHz (using the Alpha-AT) are currently supported by the Alpha active sample cell ZGS and the general purpose test interfaces ZG2 and ZG4.

Alpha-A Mainframe Options

The following mainframe options are available:
Alpha mainframe options Additional Type Code Letters
Dc bias ±40V, 70mA B if installed, missing else
High measurement speed. Support of measurement rates up to 600 impedance data points per second via GPIB port for online monitoring of fast time variant processes. F if installed, missing else


Short specification Alpha-A Rev. C mainframe (2017)
Frequency range:   3 µHz ... 40 MHz (13 decades)  max., depending on type
Frequency accuracy: 10 ppm, 32 bit resolution
Display:  bright numerical display with online status and value messages
Interfaces: GPIB / IEEE488 system control port,
DP25 Sub-D test interface connector  
Output, input connections: BNC, 3 terminals
Standalone gain phase operation
AC signal out 45 µV .. 1.36 Vrms
DC bias out only available in combination with a test interface
Signal generator output impedance 50 Ω
V1, V2 voltage channels ranges 0.045 .. 45 Vp in 13 ranges ac or dc coupled, single ended
Voltage channels input impedance < 1MΩ | 20 pF
V2 / V1 voltage ratio 3.10-4 *
Phase angle (φ):

0.02° *

V2 / V1 voltage ratio 3.10-5
Phase angle (φ):


* For details refer to specification charts