Teac DS Series Instruction Manual page 17

3.3 Calibration at Power On State
Time to Analog Circuit Stable State
At a cold start state, the analog circuit of the DS can be stable for guaranteed accuracy at
approximately 10 minutes after power activation.
When a power source is applied, the DS unit reads an internal pre-set calibration value
automatically. This process reads the pre-set calibration value recorded beforehand at ROM of
each amplifier card.
This pre-set calibration value can be renewed and updated by carrying out the manual calibration
from <INPUT AMP> menu. This calibration process carries out an internal measurement on
each channel range and each sampling frequency with internal reference voltage. This process
also calibrates with new offset value and gain of each channel, and then writes the new value into
ROM of each amplifier card.
Read "6.1.5 Manual Calibration" on how to carry out the calibration.
Periodical Manual Calibration
Periodical manual calibration each 6 months is recommended to keep good measuring precision.
Calibration Circuit Block Diagram
Switch circuit between
input and calibration
From input
Reference voltage
Overview of Calibration
Adjusting of offset value:
Zero volts are output from reference voltage source, and zero point adjustment amplifier is
adjusted in output of a D/A regenerative reactor until A/D value becomes zero.
Adjusting a gain:
Voltage of a range full scale is output from reference voltage source, and A/D value adjusts
electron volume until it becomes 100% of a range.
These adjusting results are written into a flash ROM of each amplifier.
Zero point adjustment amplifier
Range selector
amplifier
D/A converter
DS Series Instruction Manual 2006.12
Electron volume
Control logic circuit
To A/D converter
Page 9