Pioneer SX-3800 manual I I I, l * i * i i l l

O I G I T O R I V E R S E G M € N T D R I V E R

M U ! T I P L E X E R

P R E S E T A E L € 5 - D I G I T

O E C I M A L C O U N T E R

2 2 - 8 l I r 1 6 R O M

G N D

Fig . 4 - 5 Blockdiagramof PD5009

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val. Pin no.? of PD5009 is the brightnessselector terminal. The time division pulse width is set to 8009s for H level input signals,and to 200ps for

Llevel signals,thereby varying the degree of FL tube brightness (by varying the segment lighting period). Note that since the pov.er indicator FL tube is driven by static drive, the degreeof bright- nessmay be varied by changingthe grid voltage.

The 5.12MHz crystal oscillator generatesthe basic signai used in the preparation of the time division pulse signal and the counter gate circuit

control signal.

Terminals S1 - S4 (pin nos.3 - 6) are used in designating reception mode. The 2 reception modesemployed in the SX-3800 (seeTable 1) are designatedby varying the combination of input levels (H and L). The 3 different IFs during FM mode are required in coping with IF offset in the IF ceramic filter stage, 53 and 54 being preset during FM mode according to the ceramic filter characteristics.

Although the SX-3800 FM stage quartz-lock system is capable of locking any frequency within the FM band, the L0kHz digit (digit in the second decimal place) in the FM frequency display will appearonly as 5 or 0.

The frequency display FL tube alsoincorporates the TUNING and SIGNAL indicators. And al- though the segments(anode) for these indicators are static driven by the corresponding drive cir-

cuits, the edd is driven according to the D3 time divisionpulsetiming, therebyplacingthe segments

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F i g . 4 - 6 D 1 - D 5 t i m e d i v i s i o np u l s es i g n a l s

under dynamic drive. In addition, the AM and FIW indicators in the frequency display section are lit accordingto the Db timing, while the kHz and MHz indicatorsarelit accordineto the D1 timine.

MODE	s1	S2	s3	I	l F { M H z )
	H	L	L	H	1 07 3
F M	H	L	H	L	1 0 . 7 0
	H	L	H	H	't
					0.67
A M	L	H	H	L	4 5 0 k H z

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