Kenwood TS-590SG Manual page 12

01 RECEPTION
Following is a graph that provides the comparison between the performances of roofing filters.
Figure 1-5 Comparison of Bandpass Characteristics of MCFs
Figure 1-5 compares the band pass characteristics of a roofing filter of center frequency 73 MHz (gray line); and the roofing
filters of the center frequency 11.374 MHz with bandwidth of 500 Hz (blue line) and with bandwidth of 2.7 kHz (orange line)
that are both employed by the TS-590S.
Because the center frequency of the filters differ, graphs are overlapped at the center frequency. The frequency indicated
as 0 kHz at the center of the Frequency [kHz] axis is the receive frequency.
It is apparent that when down conversion is active, large attenuation is achieved at frequencies other than the target signal.
It may be difficult to understand from the figure but for a filter with a bandwidth of 500 Hz, the attenuation is approximately
70 dB and 40 dB when the frequency is detuned 1 kHz and 0.5 kHz respectively from the center frequency. Only the down
conversion configuration can use filters with this kind of characteristic.
Figure 1-6 Comparison of Dynamic Range Characteristics
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