Instrument Circuitry – Reference 3000 Schematic/Block Diagrams
20
Figure 3-2
Reference 3000 Signal-Generation Circuitry
Notes for Figure 3-2:
All the resistors summing voltages into the Summing Amplifier input do not have values shown on the
diagram. Their values depend on scaling factors too complex for this simplified diagram.
The IR DAC has a
8 V full-scale range.
Calibration components are not shown.
The DDS can generate fixed-amplitude sine waves with frequencies between 1 MHz and 1 mHz. In
practice, Gamry’s electrochemical-impedance spectroscopy software uses the Scan DAC to generate
sine signals if the frequency is below 1 Hz.
The low-pass filter removes high-frequency distortion in the “raw” DDS output.
The attenuator scales the DDS. The maximum output signal is 5.979 V peak-to-peak, and the
minimum is approximately 11
V peak-to-peak.
The BNC connector for Sig Gen out is lightly filtered using an RLC circuit.
