Hytera adopts the DMR technology and makes developments in compliance with the ETSI DMR Tier II standards.
Hytera DMR radio collects the audio signals via the microphone, converts the audio signals to analog signals, and then converts the analog signals to digital signals. In addition, the sampling signal should be strong enough to ensure high audio quality, so certain techniques are required to compress the signal. The radio can encode the audio signals by using the NVOC or CSelp vocoder in addition to the AMBE+2TM and SELP vocoders.
After sampling, the radio processes the signal through coding technology, to filter the unwanted noises and make signal compression.
The encoded signal (audio or data) is then transmitted in frames. The signal with signalling can generate a digital
data packet, which consists of the header (mainly the control and air interface information) and payload (encoded audio or data) and can be transferred over IP network. The header information repeats periodically during transmission, which makes the signal more reliable and realizes the late entry function.
The framing signal gets encoded for FM transmission. The bits contained in the digital packets are encoded as symbols representing the amplitude and phase of the modulated carrier frequency. Finally, the signal gets amplified and then transmitted.