I just obtained a Rigol DS1052E oscilloscope and so far I'm very pleased with it indeed.
For an early test I used my papilo fpga board to generate a signal using the following verilog -
module Demo(input clock, output led); reg [0:8] counter = 0; always @(posedge clock) begin counter <= counter + 1; end assign led = counter; endmodule
I connected the oscilloscope probe up to the output pin. I called it LED because it had an LED on in a previous test but it's just a diconnected pin right now, and I got this trace -
The frequency etc is all as expected, however I see spikes at each positive and negative transition. My question is, are these real? And if so are they something I would need to worry about in a real circuit if that pin was connected somewhere, or are they an artifact of the way I'm measuring the signal?
Basically am I using the 'scope correctly? As a software guy doing this for a hobby I tend to think of digital signals as purely on or off, but I know its more complicated that that so wanted to ask am I seeing something real here, and is it something I'd ever have to worry about