Digigram Releases New NTP

Digigram has announced the release of a new Network Time Protocol (NTP) feature for the company's IQOYA *LINK, IQOYA *LINK/LE, and IQOYA *SERV/LINK IP audio codecs.

Facilitating audio synchronisation via an NTP server, the feature allows radio broadcasters to assure audio for on-the-go listeners receiving signals from a series of different transmitters in a multiple-frequency FM network, as well as resolving audio delay caused when adjacent transmitters receive signals from different sources, such as satellite and terrestrial IP links.
Installed across transmitter sites, Digigram IQOYA IP audio codecs ensure that when a radio program is transmitted using several FM transmitters in a multiple-frequency network (MFN), in which all transmitters use different frequencies, the audio delay between two contiguous transmitters remains small and constant. This prevents undesired audio effects for a person in a car listening to an FM receiver that switches from one transmitter to another.
When a transmitter site receives an audio program through a terrestrial IP network and a contiguous transmitter site receives the same audio program through satellite, the IQOYA products can significantly reduce the audio delay — sometimes as long as one second — between these two transmitters.
Each IQOYA unit can be upgraded via a simple firmware update to activate the optional NTP feature, which slaves the codec's sample frequency to the clock reference given by the NTP server. The Digigram encoder can then make the associated decoder play out the audio at the same presentation time. Playback on the decoder can be delayed up to two seconds for unframed audio formats (PCM, Eapt-X) and six seconds for framed audio formats (MPEG layer 2 and 3, AAC). The smart synchronisation on the incoming IP audio stream ensures a constant delay between the decoder and the encoder.
"Enhanced with the ability to synchronise audio based on NTP servers, the IQOYA line offers an elegant solution for a critical issue that can adversely affect the listening experience," said Stéphane Bert, IP audio distribution product manager at Digigram. "Without relying on additional hardware, these IP audio codecs reduce the audio delay between two contiguous transmitters to as little as 20 milliseconds on a WAN and fewer than five milliseconds on a LAN. Guaranteeing constant delay, the systems allow broadcasters to compensate for delay and eliminate awkward gaps in audio."
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(IT/JP)