- ADPCM
- Adaptive Differential Delta Code Modulation A digital coding scheme
that digitizes a signal using normal PCM. Looks at the digitized
signal and predicts the next value. Takes the next sample and compares it with the
predicted value. Trasmits the difference between actual and predicted value.
The
predictions are being made at both ends simultaneously. Any error in prediction or
transmission will show up as aberations of the audio. This is a very efficient
transmission scheme that seems like it shouldn't work.
The most widely used coding scheme, G.722, is in fact a
standard adaptation of ADPCM. Like all algorythms, this one sounds better when you give it
more data to work with.
- AFTRS
- Armed Forces Radio and Television Service Their distribution hub is
located at March Air Force Base in California. NPR provides programming to AFRTS in two
ways.
Historiacally they have downlinked our programming directly to use in their
24-hour talk stream that is distributed worldwide to military bases.
In 1996 NPR started providing a packaged program stream that is distributed in stereo
to the same bases and ships. See Program Streams for more information or the AFTRS
Schedule for current programming.
Some of this programming makes it to over-the-air stations in various foreign
countries. The NPR Website
provides a good hunting spot to find out where our programming might be heard worldwide.
- America One
- One of three International program services provided by NPR, this one in association
with PRI. America One provides programming to european listeners
directly by satellite as well as through cable systems and some over-the-air stations. See
Program Streams for more information or the America One Schedule for current programming.
The NPR Website provides a
good hunting spot to find out where our programming might be heard worldwide.
- APR
- American Public Radio See PRI
- AT&T
- The American Telephone And Telegraph Company The company that provided
ALL audio and video inter-exchange service until the dawn of the Satellite age.
We have
cut all audio connections with AT&T but are now buying long distance phone and ISDN service from them. You can force any call on AT&T by
preceeding the phone/IDSN number with 10-288.
- AudioVault
- A Digital Audio Workstation system manufactured by Broadcast Electronics.
AutioVault
is used at NPR to delay programming and provide continuity material for three
International Services; America One, AFRTS
and USEN.
Other DAW systems at NPR include those made by Dalet and Sonic Solutions.
