The Nuova Elettronica project
A complete interface expressly designed for VA was published in issues 232 and 233 of Nuova Elettronica. The project includes input conditioning, protection and the circuits required for practical measurements.
A fully documented hardware project
The hardware was not merely an accessory. The Visual Analyser manual and the PhD thesis Virtual instrumentation for electrical measurements and uncertainty evaluation describe it as an integral part of the measurement system. In addition to the analog interface published in issues 232 and 233, a complete chapter covers the dedicated USB ZRLC hardware developed with Nuova Elettronica and published in issue 242.
The project includes A/D and D/A conversion, anti-alias filtering, signal conditioning, input protection, USB communication and the reference network used for vector impedance measurement. VA therefore becomes a complete hardware/software measurement system rather than a graphical imitation of traditional instruments.
ZRLC
The ZRLC interface turns the two audio channels into a dedicated impedance-measurement system. A known reference resistor and the device under test form a measurement network; VA acquires amplitude and phase on both channels, performs calibration and derives resistance, reactance, capacitance, inductance, complex impedance, phase angle and Q/D factors.
Dedicated ZRLC hardware
Protected connections and reference network.
Calibration and settings
Reference resistor, models, tolerances and automatic calibration.
Measurement window
Numerical and swept measurements of passive components and loudspeakers.
Vector representation
Real and imaginary components and phase can be inspected graphically.