2.16 GBAL - General Longitudinal Balance
The general longitudinal balance test is intended to measure what is
effectively the Common Mode Rejection Ratio of a transformer designed to
connect to a balanced line.
Two measurements are performed each by applying a voltage to the
transformer and measuring the resulting voltage to calculate the CMRR.
To overcome the differences of three standard methods of measuring the
CMRR the GBAL dialogue box has a separate group of terminals X and Y for
the first and second measurements respectively.
The preferred method of measurement is the LBAL test for which Voltech
provide a separate test specifically for this measurement.
This test is suitable for audio & telecommunication transformers and
checks the effective common mode rejection ratio of the transformer.
Measurement Conditions and Types
Unfortunately, there are several published specifications for measuring
longitudinal balance. These are all different, and potentially give
different results for the same transformer.
To allow each user the freedom to test to his preferred method, the GBAL
test has been configured with the greatest flexibility.
It therefore consists of two separate measurements which the user can
program, and the result is the ratio between the two expressed in dB.
See AT5600 User manual for more details.