Elecraft KDSP2 Manual - Manual (Page 45)

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Glossary
The KDSP2 introduces DSP technology to the Elecraft K2 transceiver line. There are many terms used that
are not familiar to many Amateur radio operators. This Glossary may be of help to you in understanding
these terms in the context of the KDSP2.
Adaptive Filter
An adaptive filter is one which continuously adjusts its characteristics automatically. In the KDSP2, two
types of adaptive filters are provided: autonotch and denoiser. These filters use an LMS algorithm to
suppress heterodynes (notch) or random noise (denoiser). See coefficients.
ADC
Analog to Digital Converter. This is a device which accepts an analog signal and converts it to a digital
value. In the KDSP2, the ADC accepts the signal from the K2 product detector and converts it to a 16-bit
digital value. It does this 16,000 times per second.
Algorithm
The step-by-step process followed to perform a particular task. In the case of DSP, the task is handled by
instructions to the DSP chip, known as software (if stored on a disk) or firmware (if stored in permanent or
semi-permanent memory)
Autonotch
Automatic notch filter. This type of filter attempts to reduce the strength of a very narrow range of
frequencies, typically caused by a carrier from a nearby station.
Beta
In the LMS algorithm, Beta defines how quickly the adaptive filter makes adjustments in its attempt to
implement the algorithm. If you think in terms of an automatic gain control, it corresponds to the attack
time.
A higher value means a more aggressive, or faster, attack.
CODEC
Coder-decoder. In DSP system, the CODEC contains an ADC and a DAC at a minimum. In the KDSP2,
the CODEC contains two ADCs, two DACs, programmable gain amplifiers, interface logic and power
management circuitry.