Kenwood TS-890S In-Depth Manual page 44

07 DSP
● NR1 (Line Enhancer Method)
The line enhancer method, which employs a DSP, is widely used for general noise reduction.
The line enhancer method automatically changes the FIR filter characteristics according to the frequency components of
the received signals. It provides high filtering effects particularly for periodic signals such as CW signals to improve the
S/N ratio. Because the process automatically passes and emphasizes periodic signals, it is called a line enhancer (line
enhancer method). The line enhancer employs a relatively simple signal processing system to improve the S/N ratio. At
the same time, however, it also has drawbacks such as blurring the sound when processing weak signals in the SSB
mode. It is positioned in the TS-890S as a noise reduction method for non-audio signals.
The graphs below show how NR1 improves the S/N ratio of a tone signal with the line enhancer method.
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Fig. 47 Effect of NR1 with the Spectral Subtraction Method
Fig. 48 Effect of NR1 with the Line Enhancer Method
Frequency (Hz)
Audio signal buried in the
noise is highlighted.
Frequency (Hz)
Frequency (Hz)
Noise Reduction adjacent to
Target Signal.
Frequency (Hz)