For Broadcasters
Summary table of DRM usage possibilities
By H. Donald Messer, Dr. Eng.
DRM Technical Committee Chairman
January 11, 2006
This table contains the main products/services of the DRM system. It is organized to highlight these in a manner that should be useful to broadcast managers and engineers at broadcast networks and stations.
In addition, there is text after the table that further explains current status for those table entries where development is still underway.
Finally, much more detail on the DRM system and its uses can be found in the DRM Broadcasters' User Manual.
|
Product/Services |
Applicable |
Comments |
|
DRM alone |
||
|
9/10 kHz rf channel |
LF, MF, HF |
LF: wide area coverage MF: local & wide area coverage HF: wide area coverage 26 MHz special: local coverage Audio quality: "mono FM" & partial stereo
("parametric"); |
|
18/20 kHz rf channel |
MF, HF |
Full "FM stereo" for local coverage; maybe possible
for wide area coverage; |
|
50-100 kHz rf channel |
VHF bands <108 MHz |
Highest quality approaches CD quality; |
|
Simulcast (DRM + AM or FM analog) |
||
|
18/20 kHz total (1/2 each) |
MF, HF |
DRM signal independent of AM signal; |
|
27/30 kHz total (2/3 DRM) |
MF, maybe HF |
Full stereo for the DRM part |
|
250-300 kHz total (50-100 kHz DRM) |
VHF |
Approaches CD quality; |
|
15 kHz total (10 kHz DRM) |
MF |
Special "single channel simulcast" that uses 10 kHz DRM with one analog sideband. |
In addition to the usages noted in the table, DRM includes the following features:
Single Frequency network (SFN), Automatic Frequency Switching (AFS), Multiple Frequency Network (MFN), AM Signaling System (AMSS), display of program data, low bit rate other data, such as traffic information.
1. DRM alone: 50 - 100 kHz rf channel: An extension of the "physical layer" (over the air) of the DRM standard to allow DRM transmissions in the regular VHF broadcasting allocations below 108 MHz (Bands I and II). Under development; currently rf bandwidth is determined, as well as choices for other basic variables. Laboratory simulations have begun with several propagation scenarios based upon field measurements for these bands. "DRM alone" means a 50 - 100 kHz channel can use an existing unused assignment or be "interspersed" between existing used assignments above and below it.
2. Simulcast: 27/30 kHz total (2/3 DRM): Expected to be used for "local MF" broadcasting. The rf bandwidth of the total signal may be too wide for non-linear power amplification. This product may need to be restricted to linear amplification through a transmitter. Not yet tested.
3. Simulcast: 250-300 kHz total: DRM part is the same as for 1. but is on the same channel assignment as an existing FM broadcast. The DRM part can use the same program as the FM part, or it can transmit a totally different program(s).
4. Simulcast: 15 kHz total (10 kHz DRM): A 5 kHz spectrum saving mode, using only one sideband of the AM signal. Under development as an extension of a current product only 10 kHz wide 5 AM and 5 DRM.
