Frequency activated circuit

摘要

Frequency-activated channel selector having means to increase and to decrease the lower boundary frequency of a selected channel. When the channel selector couples an input signal to a particular channel, depending on the frequency of the input signal, the lower boundary for that channel is decreased to a lower value. When the frequency of the input signal drops to or below the lower value of the lower boundary, the lower boundary frequency is increased to a higher value. This hysteresis effect eliminates anomalous channel selection behavior when the input frequency is at the channel boundaries.