KAD/LDC/101 4 channel LVDT/RVDT-to-digital converter

The KAD/LDC/101 is used for signal conditioning and digitized data acquisition from four LVDT or RVDT devices. In addition to the measurement channels, the KAD/LDC/101 provides independent excitation for four channels. Each signal has independent signal conditioning and filtering. The KAD/LDC/101 can be used with external excitation sources (400 Hz to 20 kHz), or with the independent onboard excitation outputs, which are capable of driving up to 25 mA each.

At the heart of the KAD/LDC/101 is a hard-wired state machine that over-samples all channels at a rate between 96 ksps and 192 ksps and digitally filters any noise above the user-programmable cutoff frequency. This is achieved using cascaded, half-band, decimate by 2, 15 tap, Finite-Impulse-Response (FIR) filters with 32-bit coefficients followed by an 8th order Butterworth IIR filter with a default cutoff point set at 25% of the sampling frequency. All signals are sampled simultaneously. This means that even when several channels are sampled at different sampling rates, the sample at the start of the acquisition will always be synchronized. Care must be taken when monitoring aircraft control signals due to the low input impedance when powered off.