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PicoLog 1000 Series User's Guide
Glossary
Accuracy.
The closeness between measured values and true values. This is more
usually expressed as the error, as a percentage of full scale, between the measured
value and the true value.
ADC.
Analog to Digital Converter. An ADC samples analog signals and converts them
to digital data for storage and processing. It is an essential component of a data
logger.
Analog bandwidth.
The range of input frequencies over which the measured signal
power is at least half its true value. This corresponds to a drop in amplitude of about
29%.
Duty cycle
. For a square wave signal, the proportion of the time that the signal
spends at the high level divided by the period of the signal, expressed as a
percentage. Thus, a symmetrical square wave has a duty cycle of 50%.
Input impedance.
The impedance of the input channels of the logger with the input
disconnected. Impedance is the total opposition (due to resistance, capacitance and
inductance) offered to the flow of an alternating current.
Linearity.
The ideal output of an ADC is a linear function of its analog input. Linearity
is a measure of the worst-case deviation from this ideal characteristic.
Maximum sampling rate.
A figure indicating the maximum number of samples the
ADC is capable of acquiring per second. Maximum sample rates are usually given in
accurately it can represent the high-frequency details in a signal.
Overload protection.
The maximum voltage that can be applied across the inputs of
the ADC without causing damage to it.
PWM
. Pulse-width modulation. A way of conveying analog information by means of a
single binary signal. The PWM output from the PicoLog 1000 Series units is a square
wave between 0 volts and +3.3 volts, with variable duty cycle. The average voltage of
the signal is the peak voltage, 3.3 volts, multiplied by the duty cycle.
Resolution.
A value, in bits, indicating the number of distinct input levels that the
ADC
can turn into digital values.
USB.
Universal Serial Bus. This is a standard port that enables you to connect external
devices to PCs. A full-speed USB 2.0 port operates at up to 480 megabits per second.
The PicoLog 1000 Series is also compatible with any USB port from USB 1.1 upwards.
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