The Smell of Molten Projects in the Morning

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  • Ham-It-Up Test Signal Source: Simulation

    Rather than bestir myself to measure the Test Signal Source on the Ham-It-Up upconverter:

    Ham-It-Up Test Signal source - LTSpice schematic
    Ham-It-Up Test Signal source – LTSpice schematic

    The 74LVC2G14 Schmitt-Trigger Inverter datasheet supplies useful parameters:

    Ham-It-Up Test Signal source - LTSpice Schmitt params
    Ham-It-Up Test Signal source – LTSpice Schmitt params

    All of which come together and produce a waveform (clicky for more dots):

    Ham-It-Up Test Signal source - LTSpice waveform
    Ham-It-Up Test Signal source – LTSpice waveform

    Which suggests the Test Signal ticks along at tens-of-MHz, rather than the tens-of-kHz I expected from the birdies in the filtered 60 kHz preamp response.

    Of course, hell hath no fury like that of an unjustified assumption, so actually measuring the waveform would verify the cap value and similar details.