A system for transmitting modulation in a narrow band radio frequency channel include a first signal generator configured to modulate a first signal containing data for transmission to provide a primary signal, the primary signal utilizing a higher order modulation technique than would otherwise be permissible if the first signal is transmitted separately. The system further includes a second signal generator, configured to modulate a second signal containing a pulse signal to provide a second signal, wherein the peak signal level of the second signal results in a measurement of the bandwidth of the first signal at a higher signal level and a narrower bandwidth, and a digital signal processor (DSP), which receives and combines the primary signal and the secondary signal and outputs a combined modulated signal for further digital-to-analog conversion, processing and transmission in a radio frequency band.