windell747
Mechanical
Hi,
I'm designing a circuit that will take a square wave generated by a microprocessor and feeds it through a bandpass filter to get a sine wave. The application will be to provide a tone for morse code to a handheld ham radio on board a small satellite. Right now im considering remaining simple by using a 1st order passive bandpass filter that uses a capacitor and inductor in series. Assuming this I have a few questions.
1) How should I choose the impedance of the bandpass filter? I do not know the impedance of the GPIO of the microprocessor. Does this impedance matter much?
2) What is the difference between the parallel and series configuration for the passive 1st order bandpass filter?
3) Should I filter more to get a truer sine wave? Any experienced hammers out there? I will be transmitting the morse code tone from a ham radio from a 400km orbit (LEO). I will then feed the tone through a morse decoder to convert the morse to text using a freeware program.
4) Finally, I wanted to use a passive filter to save power, however, I'm open to an active filter that uses an opamp. Are there any advantages to this?
Any guidance would be greatly appreciated!
Thanks,
Windell
4)
I'm designing a circuit that will take a square wave generated by a microprocessor and feeds it through a bandpass filter to get a sine wave. The application will be to provide a tone for morse code to a handheld ham radio on board a small satellite. Right now im considering remaining simple by using a 1st order passive bandpass filter that uses a capacitor and inductor in series. Assuming this I have a few questions.
1) How should I choose the impedance of the bandpass filter? I do not know the impedance of the GPIO of the microprocessor. Does this impedance matter much?
2) What is the difference between the parallel and series configuration for the passive 1st order bandpass filter?
3) Should I filter more to get a truer sine wave? Any experienced hammers out there? I will be transmitting the morse code tone from a ham radio from a 400km orbit (LEO). I will then feed the tone through a morse decoder to convert the morse to text using a freeware program.
4) Finally, I wanted to use a passive filter to save power, however, I'm open to an active filter that uses an opamp. Are there any advantages to this?
Any guidance would be greatly appreciated!
Thanks,
Windell
4)