The 719-01 HD Radio Delay Board is an optional drop-in accessory for our DAVID IV FM/HD Radio Broadcast Processor. It enables up to 9.999 seconds of audio delay for the Composite (MPX) and/or analog and digital program line outputs. Because there is an obligatory delay of roughly 8 seconds in the digital program encoding and decoding process present in HD Radio, the analog-FM signal must be delayed by this same amount to arrive in sync with the digital signal. This time-aligning “diversity delay,” as it is called, is enabled in the DAVID IV with this optional accessory circuit board that is simply plugged into a header strip on the main board. The delay is adjustable between zero and 9.999 seconds in one-millisecond increments, and once installed, activates new a menu adjustment, using either the front-panel jog wheel or remote PC software. Use of this accessory board requires at least Rev. 2 firmware/software in your accompanying DAVID IV FM/HD Radio Broadcast Processor.