5 ms·
If you physically cut a audio signal, one end of the cable turns into a broadcasting radio antenna. Reality isn't as simple as presented.
by coretx 6y ago
If you physically cut a audio signal, one end of the cable turns into a broadcasting radio antenna.
Reality isn't as simple as presented.
- sjruckle 6y agoHow do you figure?
- coretx 6y agoBasic physics.
- sjruckle 6y agoI'll concede that yes, technically, the disconnected wires become an antenna. The audio signal will radiate away from the section of wire between the amplifier and the switch. But the reality is that the signal is unmodulated, and the 'antenna' is a random-length pcb trace located near the ground plane. It's a terrible radiator. So if the question is "Is this an antenna that will radiate problematic amounts of rf when the switch is opened?" the answer is "No."
- jng 6y agoA low-power 20kHz signal on a PCB track not designed to radiate is not going to be a problem at all - plus you can always switch to terminating with a resistor in the unlikely case it is a problem. Also the author mentions connecting directly to the DAC, most DACs, and definitely all DACs I have studied the datasheet for have a CE (Chip Enable) signal, or some more advanced way to control audio output with a command (using an SPI or similar interface), no need to cut the audio connections. Reality isn't as simple as applying basic physical knowledge without the required context.