Rate indicator 661

direct-readingpanel-mountprecision

Measures counting rates up to 107 counts/s 18 full-scale meter ranges from 25 counts/s to 107 counts/s Fast, medium, and slow response selections offer <1%, <3%, or <10% standard deviation in the measurement Fast response circuit permits settling to 1% precision in a fraction of the normal time Positive and negative inputs Adjustable positive input discriminator Flexible analog output for strip chart recorders ORTEC Model 661 Rate Meter measures the counting rate of randomly arriving pulses, or the frequency of periodic signals in the range of 0 to 107 counts/s (0 to 10 MHz). This range of counting rates is covered with 18 different scales. The scales are arranged in a 25, 50, 100 sequence from 25 counts/s to 107 counts/s full scale. A positive input accepts and counts signals in the amplitude range of +150 mV to +10 V. The signals can be either positive unipolar pulses or bipolar pulses. With bipolar pulses, only the positive lobe will be counted. The positive input includes a discriminator whose threshold can be adjusted over the range of 150 mV to 10 V. In many cases, this eliminates the need for an external precision discriminator. Only those pulses whose amplitudes exceed the positive discriminator threshold are counted. A negative input is provided to count NIM-standard fast negative logic pulses in the amplitude range of –600 to –1800 mV. The negative input threshold is fixed at –250 mV. Pulses as narrow as 4 ns can be counted through this input.