Activity for Georgian‭

Type	On...	Excerpt	Status	Date
Edit	Post #280594	Post edited: added another image to justify a statement	—	almost 4 years ago
Comment	Post #280595	Thank you so very much Olin. What you said about the opamps requiring some time for the signals to settle makes me wonder how some PPG applications sample ambient light in between the RED and IR wavelengths for cancellation purposes. Surely ambient couldn't be sampled from the same opamps given your ... (more)	—	almost 4 years ago
Edit	Post #280594	Post edited: small typo	—	almost 4 years ago
Edit	Post #280594	Initial revision	—	almost 4 years ago
Question	—	Why are two identical filters required for each signal, if the signals can be multiplexed into a single filter? In the block diagram of this pulse oximeter design guide , in page 6, I see that the system utilizes two analog filters, one for filtering the PPG signal generated while the RED light/wavelength is 'ON', and one for filtering the signal generated while the IR light is ON. 	—	almost 4 years ago
Comment	Post #280119	Thank you. It sounds like a rookie mistake on my part, to assume the x-axes would be matched. I will perform what you suggested. (more)	—	almost 4 years ago
Comment	Post #280117	Thank you so much, that's very helpful. I confirm that the current is around 18 mA (by connecting an amperometer between R2 and the LED cathode. And I also understand how my logic was inverted, the values really make sense now. My aim is simply to have a controllable LED brightness based on the P... (more)	—	almost 4 years ago
Edit	Post #280113	Initial revision	—	almost 4 years ago
Question	—	Confused about the amplitude and shape of output voltage pulse In the circuit below, I am applying a \$3.3Vpp\$, \$63kHz\$, 50% Duty Cycle, PWM input signal at the gate of the mosfet and I am expecting to see a similar waveform with different amplitude at the LED cathode. (I am expecting \$3.3V - V{F,led}\$ when the Mosfet is ON or \$0V\$ when the mosfet is OFF... (more)	—	almost 4 years ago