Kenwood 50 MHZ ALL MODE TRANSCEIVER TS-590S - Manual (Page 40)

4 DSP
34 CONTENTS TS-590S
As a noise suppression process, the line enhancer method based on a DSP has been adopted by
many amateur radio transceivers in recent years. This method automatically adjusts the filter
characteristics according to the characteristics of a RX signal to obtain filter characteristics suitable
for passing periodic signals such as a CW signal. Because the process automatically passes and
emphasizes periodic signals, it is called a line enhancer (line spectrum enhancer). Since the
degradation of receive audio is small, a line enhancer is an easy-to-use, engineer-friendly technique.
For the TS-590S, we have reviewed part of the NR1 process and succeeded in drastically improving
the noise reduction capability compared with previous models. Below you can see the result of
frequency analysis conducted on the receive audio containing a sine wave while NR1 (based on a
line enhancer) is inactive in Figure 4-16 and the result while NR1 is active in Figure 4-17.
Figure 4-16 NR1 (Line Enhancer Method) (Inactive)
Figure 4-17 NR1 (Line Enhancer Method) (Active)
4.6.5 NR1 (Based on a Line Enhancer) (AF Processing)
Target signal
Target signal