Kenwood TS-990S Operation Manual - Page 146

6 REJECTING INTERFERENCE The center frequency of the narrow bandwidth tunable filter can be selected by moving the Preselector bandwidth. 1 Select the main band. 2 Press and hold [P.SEL] (F) while Preselector is enabled to open the Preselector screen. 3 Press [ ] (F4) or [ ] (F5), or rotate the MULTI/CH control to shift the center frequency. • You can shift and determine the filter position. Pressing [CENTER] (F1) places the filter center at the center frequency. • The default is at the center position. 4 Press [ESC] to exit. CHANGING THE IF FILTER BANDWIDTH CHARACTERISTICS SWITCHING THE RX FILTER CONFIGURATIONS The configurations (Types A, B and C) for the IF filters can instantly be switched according to your operating needs. For example, wide bandwidth characteristics can be configured for A, standard bandwidth characteristics is configured for B, and narrow bandwidth characteristics for use during the contest or with the DX station can be configured for C in advance. To search for a station you wish to communicate, you may select the filter type A with the wide bandwidth configured, and for use during the contest or with the DX station, you may select the filter type C with the narrow bandwidth configured to increasing the readability. The bandwidth characteristics can be configured by combining the roofing filter, the IF filter and the AF filter, the high frequency cutoff filter and the low frequency cutoff filter, and WIDTH and SHIFT. Also, the RX filter type (Type A, B, or C) can be configured for use in SSB, CW, FSK, PSK, FM, and AM modes respectively. Note: ◆◆Pressing [P.SEL] (F), when the frequency shifted outside the amateur band while operating in the main band, cannot enable the Preselector. ◆◆"Outside of the Band" appears when the frequency is changed while the Preselector screen is open and when that frequency would shift outside the amateur band. The key guide display will be changed to [P.SEL OFF] (F) in place of [P.SEL] (F). Pressing [P.SEL OFF] (F) disables the Preselector, and the Preselector screen closes. DSP FILTER The transceiver was designed with integral digital signal processing (DSP) technologies. Changing the filter bandwidth using the DSP function can help suppress the interference, and reduce the noise level.
4 1 Press [FIL/SEL] (M) or [FIL/SEL] (S) to switch the receive filter. Each key press cycles the RX filter type as follows: A > B > C > A. Note: ◆◆RX filter type C cannot be selected if "2" is configured for Menu 6-06, "RX Filter Numbers". 6-2 Index Contents