Abstract: A multi-channel receiver automatically determines the noise floor of each channel and resets the channel threshold based thereon while avoiding undesirable bias from weak non-noise signals. The power probability of uncharacterized input signals (non-noise content unknown) is computed and normalized to have a known probability that the power exceeds a first threshold. A second probability of exceeding a second threshold is determined and compared to a predetermined reference probability for a noise-only signal at the same threshold. If the computed second probability is not higher than the reference probability, then the uncharacterized signal is a noise only signal whose average is the noise floor for the channel. The threshold detection level is then set a predetermined amount above the noise floor. The process is automatic and compensates for receiver aging and ambient noise fluctuations with time and from channel to channel and for other changes.