The phase determines the oscillation frequency, and gain is a criterion for oscillation to exist. The four poles in the loop equation each contribute –45° phase shift accumulating the required total ...

In operational amplifier stability, one rule of thumb is to allow 45 degrees of phase margin. Other design guidelines state that 60 degrees is best; still others say that 30 degrees is sufficient.

BPSK31 is an extremely popular mode for amateur radio operators; it’s efficient and has a narrow bandwidth and can be implemented with a computer sound card or an Arduino. Just like it says on the tin ...