Circuitry after the roofing filter
Except for FM, the TS-480 has a double super: 1st IF is 73.095MHz and the 2nd IF is 10.695MHz. For FM, there is also a triple super as low as 455kHz. This is followed by analog detection and signal processing performed by the AF DSP in a standard arrangement. The AF DSP is not optional: it is equipped as standard. DSP features and characteristics are explained in the DSP section.
Three newly developed optional filters are available for the 2nd IF. Previously, there was only one 10.695MHz optional filter: the YK-107C (500Hz). This filter was developed at the same time as the TS-790, and since the focus was on its use for V/UHF, there may have been times when users felt it was lacking when it came to HF operations. So when we were developing the TS-480, we redesigned the 500Hz filter, greatly improving its shape factor. We also used the opportunity to design new 270Hz and 1.8kHz (SSB narrow) filters.
Fig. 11 graphically illustrates the difference between these filters in the 500Hz band.
Fig. 11: Comparison of optional CW filters (500Hz)
18
