PowerTek PA2553, User Manual, Page: 13 / 88

Functional Description 13
Functional Description
This chapter describes the circuitry and interfaces of the
PA2553
/
PA2553E
.
Theory of Operation
The
PA2553
/
PA2553E
is high performance test equipment. Within the analyser, voltage
and current signals are converted to digital data using DSP chips where the signals are
sampled automatically and periodically. A to D converters scale and sample data. The
data-analysis components analyze voltage and current input samples for harmonic
content.
The following is a list of the significant components and a description of their function
within the analyser.
Voltage Attenuators —Resistively attenuate the voltages present on the SOURCE A, B,
C and N terminals to a 2.5V peak-amplitude maximum voltage signal.
Hall Effect Transducer —Converts the current flowing from each phase SOURCE to
LOAD into isolated voltages of the
PA2553
.
Analog Anti-Alias Filters —Reduce the bandwidth of the signals applied to the inputs of
the ADCs to less than the sampling frequency.
Each of the attenuator outputs and the outputs of the Hall Effect transducers are
passed through identical analog anti-alias filters.
16-Bit A to D converters (ADC ) and First In/First Out memory (FIFO) —
The ADCs digitize each signal with 16-bit resolution at the DSP generated
Sample Clock frequency. The FIFOs store each digital sample in memory to be
read by the DSP in blocks of 32 samples per converter.
80 MIPs Digital Signal Processor (DSP) —Processes the tasks required to compute the
multiple voltage, current, and power results. Also processes the tasks required to
format the results for display, printout and interrogation via the IEEE488
interface. Computed results are independent of the selected display and
IEEE488 interface requirements.