Compatible Amplitude Modulation - Digital or CAM-D is a
hybrid
Hybrid may refer to:
Science
* Hybrid (biology), an offspring resulting from cross-breeding
** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species
** Hybridity, the property of a hybrid plant which is a union of two dif ...
digital radio
Digital radio is the use of digital technology to transmit or receive across the radio spectrum. Digital transmission by radio waves includes digital broadcasting, and especially digital audio radio services.
Types
In digital broadcasting syst ...
format for
AM broadcasting
AM broadcasting is radio broadcasting using amplitude modulation (AM) transmissions. It was the first method developed for making audio radio transmissions, and is still used worldwide, primarily for medium wave (also known as "AM band") transmis ...
, proposed by
broadcast engineer
Broadcast engineering is the field of electrical engineering, and now to some extent computer engineering and information technology, which deals with radio and television broadcasting. Audio engineering and RF engineering are also essential pa ...
Leonard R. Kahn.
The system is an
in-band on-channel
In-band on-channel (IBOC) is a hybrid method of transmitting digital radio and analog radio broadcast signals simultaneously on the same frequency. The name refers to the new digital signals being broadcast in the same AM or FM band (in-band), a ...
technology
Technology is the application of knowledge to reach practical goals in a specifiable and reproducible way. The word ''technology'' may also mean the product of such an endeavor. The use of technology is widely prevalent in medicine, science, ...
that uses the
sideband
In radio communications, a sideband is a band of frequencies higher than or lower than the carrier frequency, that are the result of the modulation process. The sidebands carry the information transmitted by the radio signal. The sidebands co ...
s of any AM
radio station
Radio broadcasting is transmission of audio (sound), sometimes with related metadata, by radio waves to radio receivers belonging to a public audience. In terrestrial radio broadcasting the radio waves are broadcast by a land-based radio ...
.
Analog
Analog or analogue may refer to:
Computing and electronics
* Analog signal, in which information is encoded in a continuous variable
** Analog device, an apparatus that operates on analog signals
*** Analog electronics, circuits which use analog ...
information is still used up to a
bandpass
A band-pass filter or bandpass filter (BPF) is a device that passes frequencies within a certain range and rejects (attenuates) frequencies outside that range.
Description
In electronics and signal processing, a filter is usually a two-port ...
of about 7.5
kHz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that on ...
, with standard
amplitude modulation
Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the amplitude (signal strength) of the wave is varied in proportion to ...
. The missing
treble information that AM normally lacks is then transmitted
digital
Digital usually refers to something using discrete digits, often binary digits.
Technology and computing Hardware
*Digital electronics, electronic circuits which operate using digital signals
**Digital camera, which captures and stores digital i ...
ly beyond this. Audio mixing in the
receiver then blends them back together.
Unlike other
IBOC
In-band on-channel (IBOC) is a hybrid method of transmitting digital radio and analog radio broadcast signals simultaneously on the same frequency. The name refers to the new digital signals being broadcast in the same AM or FM band (in-band) ...
technologies like
iBiquity
iBiquity Digital Corporation is a company formed by the merger of USA Digital Radio and Lucent Digital Radio. Based in Columbia, Maryland, with additional offices in Basking Ridge, New Jersey, and Auburn Hills, Michigan, iBiquity is a privately ...
's
HD Radio
HD Radio (HDR) is a trademark for an in-band on-channel (IBOC) digital radio broadcast technology. It generally simulcasts an existing analog radio station in digital format with less noise and with additional text information. HD Radio is used ...
, Kahn's apparently does not provide a direct path to all-digital
transmissions, nor any
multichannel capability. Its advantage, however, is that it takes up far less of the sidebands, thereby causing far less
interference
Interference is the act of interfering, invading, or poaching. Interference may also refer to:
Communications
* Interference (communication), anything which alters, modifies, or disrupts a message
* Adjacent-channel interference, caused by extr ...
to
adjacent channel
In broadcasting an adjacent channel is an AM, FM, or TV channel that is next to another channel. First-adjacent is immediately next to another channel, second-adjacent is two channels away, and so forth. Information on adjacent channels is ...
s, hence the "
Compatible
Compatibility may refer to:
Computing
* Backward compatibility, in which newer devices can understand data generated by older devices
* Compatibility card, an expansion card for hardware emulation of another device
* Compatibility layer, compo ...
" in the name. Interference has affected HD Radio on AM, along with its (like CAM-D)