Phased digital filtering in multichannel environment

DETAILED DESCRIPTION A specimen, such as automobile, being subjected to simulated road conditions, is mounted at its wheels or wheel spindles on supports through which multidirectional motion is applied to the vehicle.
The supports are moved by motion actuators which respond to analog command signals.
Transducers attached to the automobile develop analog output signals relating to motion, force, strain, and other measurable factors.
A plurality of transmission channels are provided for the transmission of transducer outputs and analog command signals, generally with a channel being associated each transducer and each motion actuator.
A digital signal processor provides for decimation of the transducer output signals, after analog to digital conversion, and for interpolation of the motion actuator command signals, which are subject to digital to analog conversion.
The digital signal processor executes parallel multistage, multirate digital filters on incoming signals representing the outputs of the transducers.
The digital data streams on each channel are digitally filtered, preferably by execution of appropriate commutator routines in the digital filter for each channel, resulting in a decimated representation of the analog output signal for each channel.
Commutator operations are phase staggered between channels to avoid coincidence of mathematical processing demands on the digital signal processor.
Decimated digital data signals are transferred to a data analysis computer.
The digital signal processor also provides for interpolation of analysis computer control signals and transmission of the interpolated signals onto the channels to the motion actuators.
Again, the digital signal processor executes parallel multistage, multirate digital filters on the command signals generated by the analysis computer.
Commutators in the digital filters are staggered in phase from channel to channel, again to avoid coincidence of certain subfilter operations between channels.
The digital signal processor, through a digital to analog converter transmits the data point enhanced analog servo command signals out to actuators, such as servohydraulic actuators, for carrying out the simulation regimen employed to the specimen