Designed for MFN, SFN, and STL applications, the APT Codec 4.0 includes several new features and enhancements. The most significant include the revolutionary APTmpX algorithm and SynchroStream, both available as software options.

• APTmpX: the world’s first and only non-destructive MPX/composite compression algorithm to save network bandwidth while maintaining the original composite signal quality.
• SynchroStream: a new APT technology for precise and stable time-synchronous IP transmission and playout of audio content. It is the most effective tool for optimizing analog FM-SFN networks with the most precise time alignment. SynchroStream allows to move mush zones in the narrowest steps of less than 50 meters in the field. SynchroStream is supplied as a software option on the existing APT IP Codec range and equips the APT IP Codec for use in FM-SFN networks (IP Codec hardware rev. 3 required). SynchroStream utilizes an externally supplied 10MHz clock and the 1pps signal as time reference (e.g., from satellite). 

Users also benefit from:

• Precision clock module for GPS: Hardware option to apply the external clock from a GPS receiver (for APT IP Codec rev. 3).
• NTP – Content time alignment: With the NTP based content time alignment feature, 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 enables the same program to broadcast on different carrier frequencies (MFN); these programs are temporally aligned and kept within the limits of the perceptual ability by the human ear.
• NAT transversal connection mode: Dynamic IP address assignment and the NAT of a cellular network prevent reliable program supply to a transmitter through the network’s air interface. The NAT traversal mode eliminates these barriers and allows to run stable cellular STLs.