38
R
RDS (Radio Data System)
RDS tuners can automatically tune in stations
according to the types of music (or talk)
they broadcast. RDS also enables a receiver
to display text messages and even graphics
(usually call letters and format information)
that many FM stations include on a sub-carrier
signal within their normal broadcast signal.
Some RDS equipped tuners can even override
with traffic alerts or emergency broadcasts,
during playback of other media - CD MD, or
cassette. There are other useful features too,
many of which are offered by the growing
number of RDS stations.
RF (radio frequency)
An alternating current or voltage with a
frequency (or carrier wave) above about
100kHz. It is called radio frequency because
these frequencies have a capacity to be
radiated as electromagnetic waves by radio
(and television) stations.
Rip (ripping)
Using a software program that “grabs” digital
audio from a compact disc and transfers it to a
computer hard drive. The integrity of the data
is preserved, because the signal does not pass
through the computer sound card, and need
not be converted to an analog format. The
digital-to-digital transfer creates a WAV file
that can then be converted into an MP3 file.
RMS (Root Mean Square)
A formula that provides a reasonably accurate
means to measure and compare continuous
AC power. The use of this measure is
preferred when matching system components,
like amplifiers and receivers.
S
S/PDIF (SPDIF) (Sony/Philips Digital
Interface)
A standard audio-file transfer-format that
was developed jointly by Sony and Philips. S/
system with the ‘.m4a’ filename extension.
M4A can produce better audio quality than
MP3 using less physical space for the files.
MHz (Mega Hertz)
One million cycles per second.
Midrange
The middle three octaves (more or less)
of the audio band, where the ear is most
sensitive, usually between 160Hz-3kHz.
Mono (monaural)
The operation of an amplifier in one channel
for both input and output. Can refer to
an amplifier with only one channel of
amplification or operating in bridged mode.
For low-frequency amplification applications,
it provides better phase coherence and less
distortion than stereo operation.
MP3
A file format with a sound data compression
system. MP3 is the abbreviation of Motion
Picture Experts Group 1 (or MPEG-1) Audio
Layer 3. With the MP3 format, one CD-R or
CD-RW can contain about 10 times more
data than a regular CD.
Mute
A control found on receivers, and some
mixers or signal processing units that silences
(mutes) a signal path, or output.
O
Ohm
Measure of resistance to current (impedance).
The lower the impedance of a speaker, the
harder it is to drive.
P
PCM (Pulse Code Modulation)
Pioneering form of digital recording.
EN
