Chapter 6 -- Instrument Circuitry--Interface 1000 Schematic/Block Diagrams
6 - 4
Figure 6-3
One A/D Signal Chain in the Interface 1000
Notes for Figure 6-3:
• This diagram shows one of two identical ADC channels. One channel is dedicated to measurement of
the potentiostat’s current signal and the other is used to measure the voltage signal.
• Both A/D converters are triggered simultaneously to start a conversion. This trigger and the pulse
updating the Scan DAC voltage are under the control of a hardware state-machine. This insures that all
waveform and data acquisition timing is tightly controlled and reproducible point-to-point.
By default, the data acquisition is synchronized with the system's 600 kHz power supply switching
frequency reducing noise due to the power supply. Data acquisition times that are a multiple of
1.666 µSec will maintain this synchronization.
• All analog signals are received differentially as shown here.
• The 5 Hz, 1 kHz, 10 kHz, 200 kHz and 1.4 MHz filters are 2-pole Butterworth filters.
• The voltage measurement channel includes a programmable 1x - 0.25x gain circuit. In the 0.25 gain
position, voltages as high as 12 volts can be measured.
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