4/18/11
888-2587-001
1-5
WARNING: Disconnect primary power prior to servicing.
Section 1 Introduction/Specifications
FM HD Radio System
MPS PAD
- Main Program Service Program Associated Data. Program related data
such as song title and artist information. Delivered in the iBiquity protocol from the
station’s audio hard disk storage system via an Ethernet or RS232 communications port.
This data is then fed to the HDE-100 Exporter and is displayed as text on the HD
receiver.
Separate Amplification
- Two transmitters are used; one for FM only and one for HD
only.
Separate Antennas
- A low-loss, space-combining technique that employs the station’s
existing FM main antenna, and the station’s licensed auxiliary antenna for transmitting
the HD Radio sidebands. The analog and digital signals are effectively combined in
space. The primary advantage of using separate antennas is very low loss to the HD
signal, significantly reducing the HD transmitter power requirements. The primary
disadvantage is unequal azimuth radiation patterns and resulting reception variation of
the analog to digital signal ratios.
Split Level Combining (SLC)
- A Harris exclusive method of developing a hybrid
IBOC signal using a combination of separate amplification and common amplification.
Today’s systems utilize a 3dB, 4.77dB, or 6dB hybrid combiner to make the most
efficient use of the existing analog transmitter, and to properly size the digital
transmitter to be capable of the digital-only power levels in the future. SLC also
provides minimum combiner losses, maximum combining efficiency, and improved
overall AC to RF efficiency compared to Separate Combining.
SPS
- Supplemental Program Service. Also referred to as Supplemental Audio Service,
Supplemental audio programming (1 to 4 additional ’channels’) is input to the HDI-100
Importer in AES3 digital format.
SPS PAD
- Supplemental Program Service Program Associated Data. Identical to MPS
PAD, but for any of the SPS audio programs.
SRC
- Sample rate converter.
Switch
- Ethernet distribution device that is more spohisticated than a hub.
TCP IP
- Transmission Control Protocol/Internet Protocol.
UDP
- User Datagram Protocol. A simple unidirectional communication protocol that
sends, but requires no acknowledgement of packets being received.
1.3.1
Ensemble Operations Center Description
The following paragraphs provide a brief description of the various EOC software
components used in the HDI-100 Importer.
