A little explanation about DMR and dPMR standards may be of interest.
To reduce the congestion present in today’s crowded radio spectrum, radio channels must be used more efficiently.
The basic idea is to divide existing radio channels in half, thus doubling the number of channels available.
The term “frequency” which most people are aware of, is actually only a spot centre frequency in the middle of a small band of radio spectrum (a channel).
Before.
After.
Historically, this “dividing” has happened a number of times over the years. As analogue radio technology improved, existing channel widths were cut in half.
Unfortunately, there came a point when it seemed that this technique could no longer be used.
Many were of the opinion that the physical limits of analogue filtering technology had reached a plateau and was not capable of narrower channel widths.
Some manufacturers, however, were of the opinion that a combination of digital and traditional analogue techniques made physical channel division a viable proposition.
So, there have been effectively two technologies researched and developed alongside each other.
The dPMR standard which relies on FDMA (Frequency Division) techniques, which relies on the old analogue way of physically dividing an existing channel.
And the DMR standard relies on TDMA (Time Division) techniques, which relies on creating two 2 “virtual” channels within a single existing channel by transmitting information in “time slots”.
Of the two technologies, the dPMR was (theoretically) technically easier to implement, making it the cheaper option.
Even now, the two camps are using various “marketing” press releases and other documents to extol the virtues of their own technology.
Each time advantages / disadvantages are highlighted by one side, advances in technology renders their arguments null and void.
It seems that because both technologies are still in their infancy and are constantly evolving and improving, the argument about which standard is “the best” will not be settled anytime soon.
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