I chose to look at the frequencies in the low range of CTCSS tones (67 to 100Hz) because these are the closest together, with a minimum tone spacing of 2.5Hz between tones 2 (71.9kHz) and 3 (74.4kHz), ...
Short-range-radio co-existence is now possible using CTCSS carrier generation with a 256-B sine-wave lookup table. To allow multiple users to share one carrier frequency, many handheld transceivers ...