Tektronix 2467 Observing Coincidence of Digital Signal

Discussion in 'General Electronics Chat' started by SamEricson, May 2, 2015.

  1. SamEricson

    Thread Starter Member

    Apr 25, 2015
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    In the Tektronix 2467 oscilloscope manual there is a TTL/CMOS logic measurement that I don't understand how they are using it. Can you guys please read this and see how they use this feature to troubleshoot logic TTL/CMOS circuits.

    Observing Coincidence of Digital Signals

    With digital signals applied to CH 1 and CH 2, the Add waveform is high when both signals are high, low when both are low, and at an intermediate level when one signal is high and the other is low. By inverting CH 2, you can observe the coincidence of one signal and NOT the other. To observe coincidence of TTL signals:

    1. Connect the signals of interest to CH 1 and CH 2. If the coincidence of interest has one signal high and the other one low, invert CH 2.

    2. Display CH 1, CH 2, and Add. Set both VOLTS/DIV to 2 V and both inputs to GND. Position both channels on screen and the Add trace one division above the bottom of the graticule. Then deselect CH 1 and CH 2.

    3. Set both inputs to DC. Set Trigger mode to Auto and Source to Vert. If the coincidence of interest is high-high, set trigger SLOPE to -t-. If the coincidence is low-low, set SLOPE to - . (If CH 2 is inverted, consider the inverse of the CH 2 signal in the high-high or low-low combination.) Press INIT@50%, then carefully adjust the trigger level to respond to the high-high or Low-low state combination. (Trigger level readout doesn't operate with Add Source.)

    4. Now you can observe and measure coincidence durations and other time intervals. Channels 3 and 4 can show relationships to other signals.
     
  2. #12

    Expert

    Nov 30, 2010
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    Not a chance. If you can't understand what a resistor substitution box is for, you can never understand how to follow these instructions, no matter who or how many people explain it to you.
     
  3. crutschow

    Expert

    Mar 14, 2008
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    I somehow have a feeling we are dealing with the reincarnation of a previous forum nemesis. :rolleyes:
     
  4. #12

    Expert

    Nov 30, 2010
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    I can't remember who went around in circles forever without ever posting a schematic, brand name, model number, available equipment, or even properly defining what the question is.

    Just lucky, I guess. :p

    Drags out old lists...

    AustinClark, BillyMayo, DMahalco, Dexter McCoy...

    That was before I found the, "Ignore" function.
     
    Last edited: May 3, 2015
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