Digital Two Way - Q & A
Most heavy radio users rely on analog radio and have concerns about leaving the path they're used to and that's gotten the job done year after year. But the truth is that while analog radios may get the job done, they've pretty much reached their limit in terms of innovation and advancement. Times are changing, and many organizations are finding that they have more needs than the capabilities analog two-way radios can deliver, and they are searching for better options to improve efficiency and performance. It’s also important to remember that digital radios can operate in an analog mode, so you don’t have to completely abandon your current analog operations.
Here are the answers to your concerns and curiosity about how digital radios work and how they can help rather than hurt you.
Q: My new digital radio sounds different than my old analog radio. Why?
A: Digital radios sound different because of the voice compression used to encode and transmit audio using a 6.25 KHz channel.
Background: Under narrow band initiatives found in many regions, 2-way radios are allowed to use 12.5KHz of bandwidth for each transmit channel. Analog radios can only transmit one voice channel using this spectrum. Using voice compression and the DMR protocol, digital radios can transmit two voice channels using the same bandwidth. As a result, digital radios have twice the capacity as analog radios. In addition, digital radios support advanced features such as voice encryption which are not possible using legacy analog radio technology.
Q: Do digital radios have better range?
A: Yes, for most users.
Background: One of the strengths of the MotoTRBO digital radio is its ability to transmit clear intelligible audio over an extended geographical region when compared to an analog radio system. However, unlike analog radio systems, when a digital radio operator reaches the edge of his coverage region the audio may begin to sound “robotic”, “mechanical” or “broken” before the audio signal drops-out altogether. In an analog radio system, the audio simply becomes more and more faint with increasing levels of background static as the RF signal fades out.
Q: My digital radio doesn’t sound like my digital MP3 player. Why?
A: MP3 players have more than 5 times the amount of data available to reconstruct the encoded audio and, as a result, are able to provided audio that sounds very close to the original.When the amount of compression required to use a 6.25e KHz channel is clearly understood, the audio intelligibility achieved in the encode/decode process is really quite impressive.
Q:How does my digital radio achieve greater RF efficiency?
A: Analog radios can only transmit one voice channel using this spectrum. Using voice compression and the DMR protocol, digital radios can transmit two voice channels using the same bandwidth. As a result, digital radios have twice the capacity as analog radios. In addition, digital radios support advanced features such as voice encryption which are not possible using legacy analog radio technology.
Q: How does the range of a digital radio compare to my analog radio?
A: First, it’s important to understand that some reduction in range is expected going from 25KHz channels to 12.5KHz channels (with Analog). Digital Radios provide greater RF range when all things are equal.
Q: Sometimes I hear an echo on my digital radio. Why?
A: The “echo” heard in a digital communication system is more accurately termed “System Delay”. It is caused by the small but measureable amount of time it takes to compress the audio and acquire the necessary channel synchronization for transmission. Echo (i.e. System Delay) in a digital radio system is commonly heard when a receiving radio is located in close proximity to the transmitter. Depending on the system configuration, the system delay may range from 60mS to over 900mS.
Q: It seems like it’s harder to hear my digital radio. Why?
A: The received audio in a digital radio system is “reconstructed” from compressed data. The reconstructed audio lacks some of the frequency content found in the original voice audio.
Background: A small amount of missing frequency content is not a problem for most people who have typical hearing abilities. However, for listeners who have some hearing impairments the missing content may make it difficult to clearly understand the radio transmission.
Q: Does my digital radio work in a high-noise environment?
A: Digital radios can work well in environments where the ambient noise ranges from 110 -118 dB Sound Pressure Level (SPL). At noise levels higher than this, specialized noise reduction strategies are needed.
Digital radio has worked its way into all types of organizations, from manufacturing plants to laboratory campuses to healthcare facilities. Once you get to know more about how it works and what it offers you'll probably find there's something that will help your business.
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For more information, read other articles about Analog vs. Digital here.