In an all digital system, how does Harris propose we insert EAS signals and where?
The HD Radio system all digital specification calls for EAS type functionality in the advanced application services. In the HD Radio hybrid mode, the EAS tone/audio source would need to be inserted ahead of the first conversion to an AES audio stream. When the system converts to an All-Digital mode there will need to be a small segment of the data bandwidth reserved for EAS or some equivalent emergency alert system. This should not be a problem even for AM given the small amount of data required to transmit the emergency codes, warning signals and text. There should also be opportunities to implement other systems such as Amber Alert, traffic codes, weather alerts, etc. This type of data would be injected into a data port of the HD Radio exciter or a data port on some other data management hardware. The exciter or other hardware will then multiplex all data sources (including program audio) together and then modulated onto the RF carriers.
