Incorporating the latest developments in counter technology the LF 827 extend high resolution readings over very wide frequency ranges and make use of calculator modes to meet the needs of assembly line and quality control applications. A technique of high speed reciprocal counting is applied to input A signals to produce high resolution at low frequencies. (Older counters required period readings with calculated reciprocals to obtain similar resolution). Direct counting is applied above 10 MHz and a prescaler technique is applied to B input signals above 80 MHz. The result is accurate, high-resolution reading across the entire frequency range. Measuring modes include frequency, period, relative, totalizer and RPM for input A signals. Automatic and manual trigger levels are also applied to input A signals to suit trigger conditions to signal characteristics and to achieve stable readings in the presence of noise. A switchable low pass filter, cutoff below 100 kHz, allows accurate low frequency readings in the presence of RF interference. Sensitivity is excellent: 15 mV rms for input A and 10 mV rms for the B (prescaler) input. Built-in calculation capabilities include relative and a LO-GO-HI comparator judgement modes. The relative mode works from an operator-preset parameter and reads out the deviation from that preset value with 7-digit resolution. The comparator function works with a pair of preset parameters and indicates low, within limits, or high readings by means of front panel LO, GO or HI LED's. Timebase accuracy is ± 3 ppm. Factory options for the LF 827 include a ± 0.03 ppm timebase and a GPIB interface.
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