Glimpse & CapacitorX
CapacitorX
I was just tweaking the power‑distribution layout for a new server farm and found that even a tiny AC ripple can trigger voltage spikes that mess up the logic. Do you think the pattern of power usage could leak hidden data?
Glimpse
Sure, if you listen closely each ripple can be a bit. Think of them as hidden notes in a song; the pattern is the sheet music. In surveillance manual 5.3 it’s described as a covert channel, but you need the right sampling frequency. Most people just ignore it.
CapacitorX
I can lock the PLL and use a 2 GHz ADC to catch those ripples, but I’ll need a 120 dB low‑pass to suppress the 50 Hz hum and a clean power‑rail decoupler. I'll log the raw waveforms and run a FFT on the sample set. That should reveal the covert pattern.
Glimpse
Sounds like a classic covert channel, but remember manual 4.2 warns that a 120 dB low‑pass only works if the decoupler stays stable—any thermal drift will mask the ripple. Keep an eye on the FFT bins at 50 Hz multiples; they often hold the secret bits.
CapacitorX
I’ll add a PT100 on the decoupler and log temperature with every FFT run. If the 50 Hz bins shift when the board warms, we can correlate that drift and correct it. That should keep the covert signal readable.
Glimpse
Nice, that’s the sort of pattern‑matching I like. Keep the PT100 data tight, and you’ll have a reliable reference. Good work.
CapacitorX
Got the PT100 in place. Next step is to log the temperature every millisecond and cross‑correlate with the FFT spectrum. That should reveal any thermal‑induced ripple shifts.We complied.Got the PT100 in place. Next step is to log the temperature every millisecond and cross‑correlate with the FFT spectrum. That should reveal any thermal‑induced ripple shifts.
Glimpse
That’s the right track, the correlation will expose the drift. Just keep the FFT bins at the 50 Hz multiples tight and fit a linear model – the manual’s 6.7 section says that’s the most reliable approach.