Description
The SD4001 is CMOS LSI chips developed for world-wide FM / MW / LW tuning with PLL frequency
synthesizer system. The SD4001 can make a compact and high performance FM / MW / LW tuner
with clock function for high-end car stereo,   home stereo and so on because these CMOS LSIs are in
64-pin QFP package with built-in PLL frequency synthesizer, controller, 200 MHz prescaler, LCD
driver and IF counter.

Functions
Radio Functions
(1) Manual tuning 
    Manual tuning up/down ….. Stepped tuning an d rapid tuning.
(2) Auto tuning 
    Seek up/down ….. Retaining the frequency of a station received.
    Scan up/down ….. Receiving in intervals of 5 seconds.
(3) Preset memory scanning ….. Receiving the contents of preset memories on the FM, MW.
and LW bands for 5 seconds each.
(4) VF auto – tuning
    SK seek up/down …. Retaining the frequency of a SK signal received.
    SK scan up/down …. Receiving a station with SK signal in intervals of 5 seconds.
(5) Preset memories
    FM band …. FM 1:6 stations, RW 2:6 stations, FM 3:6 stations
    MW band … MW 1:6 stations, MW 2:6 stations
    LW band … 6 stations
    VF band …. 6 stations
    MW2 cannot be used while the LW band is used.
(6) Last-preset memories …… 1 station on the FM1, FM2, FM3, MW1, MW2, LW and VF
bands each.
(7) LOC (local) control signaloutputs and indications.
(8) FM MONO (monaural) control signal output and indication.(For VF bands, same as for FM)
(9) “ST” (stereo) indicator …… Enabled on the FM and VF bands.
(10) Auto-preset memories
(11) DK stand-by and SK alarm function

Tape Functions
(1)  Tape transport direction indictors ….. Can flash at 2 HZ during fast forward.
(2) AMS (auto music search) control signal output and indication.
(3) MTL (metal) control signal output and indication.
(4) NR1 (noise reduction) and NR2 control outputs and indications.

Functions (Continued)
CLOCK Functions
(1)  Selectable 12-hour(with AM and PM indicators) of 24-hour display.
(2)  Selectable flashing colon(;) (1Hz)
(3) Low-power (10µA) backup available in the NOCLK(no-clock)mode.

Others
(1)  LOUD (loudness) control signal output and indication ….. common to radio, tape and CD 
modes.
(2) Key acknowledge(beep) signal outputs (2.25 kHz, 40ms) ….. Enabled by valid 
momentary keys.
(3) Display selector and priority display function.
(4) ““ (complex disk) indicator.