The DBu transmitter is a second generation design with specially developed, high efficiency digital circuitry for extended operating time on two AA batteries. The transmitter can tune in coarse or fine steps across the UHF television band from 470.100 to 607.950 MHz, with a selectable output power of 25 or 50 mW. The pure digital architecture enables AES 256-CTR encryption for high level security applications. Studio quality audio performance is assured by high quality components in the preamp, wide range input gain adjustment and DSP-controlled limiting. Input connections and settings are included for any lavaliere microphone, dynamic microphones and line level inputs. Input gain is adjustable over a 44 dB range in 1 dB steps to allow an exact match to the input signal level, maximizing the dynamic range and signal to noise ratio.