Spike Detector For Oscilloscopes


Posted on Feb 7, 2014

Dynamic‚ip-‚ops ignore pulses at their inputs that are shorter than 40 ns or do not have TTL levels. This means that TTL flip-flops are poorly suited to capturing noise pulses having unknown durations and magnitudes. Anyone who has ever tried to observe very short laser pulses (15 25 ns) is familiar with this problem. By contrast, this circ


Spike Detector For Oscilloscopes
Click here to download the full size of the above Circuit.

uit can detect impulses with widths less than 8 ns and amplitudes between +100 mV and +5 V. The heart of this circuit is formed by a MAX903, a very fast comparator with internal memory. The IC has separate supply pins for its analogue and digital portions. The analogue portion is powered by a symmetrical ±5-V supply. This allows the detector to also handle input voltages that are negative relative to ground. The internal memory and output stage operate from a single-ended +5-V supply, so the output signal has proper TTL levels. The MAX903 (IC1) has a special internal memory circuit (latch). The latch either connects the output of the internal comparator directly to the signal output or stores the most recent TTL level and blocks the output of the internal comparator, causing the most recent TTL level appears at the output. This allows short input pulses to be stretched to any desired length. Despite its extremely short switching times, the MAX903 consumes only a modest 18 mW. In the quiescent state, the voltage on the Latch input (pin 5) is at 1. 75 V. This reference voltage is provided by LED D1, which draws its current via R2. In this state the latch is transparent, and a positive edge at the input appears will appear as a negative transition on the output after a propagation delay of 8 ns (tPD). This only happens if the peak voltage on the input is more positive than ground potential. C1 passes this change in the output...




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    LASER Transmitter/Receiver
    Square·-to-sine-wave-converter
    Hall-effect-compass
    Buck Boost Voltage Converter
    Car Battery Saver Circuit
    20w rf fm amplifier circuit
    Digital Radar Speedometers
    Wideband Low Noise Amplifier
    2 line intercom plus a telephone changeover switch
    N5ESEs QRP Dummy Load With Built-in RF Detector
    Control circuit of automatic water



    Top