I have a crystal oscillator (full can) running at
14.31818 MHz. When I put that on my scope, it shows about 14.3~ MHz. My scope is a
Rigol DS1102E 100 MHz so I understand that you need about 10x the frequency of what you're measuring so I would need about 140+ MHz scope to accurately see the 14.31818 MHz frequency. So I get that. Anyway, oscillator seems to be working.
Next, I wanted to "square out" the wave a little by running it through a
SN74AC04 HEX inverter. So when I tie the output of my oscillator to
A0 I get nothing but a flat line on
So thinking maybe the '04 was bad, I swapped it out. Same thing.
Next, I decided to back down the frequency. So I plugged in my
SIGLENT SDG805 waveform generator into
A0 (I unplugged the oscillator).
I then tried different frequencies. Starting at 1 KHz all the way up to 5 MHz (the maximum I can generate with the SIGLENT). The scope shows a very nice square wave for the most part. 5 MHz is a little off but the scope shows pretty much the same thing as if I had a 5 MHz crystal.
Anyway, why does the 14 MHz oscillator show a flat line? The specs of the '04 say (from what I understand) that it should be able to handle that frequency.
I'm running everything at
The specs say
tPHL at 3.3v should be about
9.5ns respectively. 10ns should allow 100 transitions per micro-second right?
So wouldn't I get around 6-7 transitions at 14 MHz?
Anyway, what am I doing wrong?