The country’s FM spectrum is congested, and attempts to free up some of the spectrum for new players is proving difficult
WorldCast Systems has released APT 4.0 for APT IP, AoIP multichannel and MPX multichannel codecs.
Designed for MFN, SFN, and STL applications, new features of APT Codec 4.0 (SR 4.0) include the APTmpX algorithm and SynchroStream. Both are available as software options.
The company describes APTmpX as a non-destructive MPX/composite compression algorithm for saving network bandwidth while maintaining the original composite signal quality.
SynchroStream is a new APT technology designed to facilitate precise and stable time-synchronous IP transmission and playout of audio content. The tool optimizes analog FM-SFN networks with precision time alignment.
Worldcast points out that SR 4.0 also offers NTP-based content time alignment, where the encoder determines the target latency of an IP link to the transmitters. With SR 4.0, the timing is controlled by timestamps on the IP packets. This enhancement, the company says, enables the same program to broadcast on different carrier frequencies (MFN), with the programs temporally aligned and kept within the limits of the perceptual ability by the human ear.
In addition, the upgrade has a NAT transversal connection mode for stable cellular STLs. And the codecs have a hardware option to use an external clock from a GPS receiver (for APT IP Codec rev. 3).