Epson S1C63558 7.7 FSK Demodulator Characteristics, Timing chart, Band-passfilter gain (Typ. value)

CHAPTER 7: ELECTRICAL CHARACTERISTICS

7.7 FSK Demodulator Characteristics

Unless otherwise specified:

VDD=5.0V, VSS=0V, fCLK=3.579545MHz, Ta=-20 to 70°C

Item	Symbol	Condition	Min.	Typ.	Max.	Unit
Transfer rate	TRATE		1188	1200	1212	Baud
Bell202 mark (logic 1)	fB1		1188	1200	1212	Hz
frequency
Bell202 space (logic 0)	fB0		2178	2200	2222	Hz
frequency
ITU-T V.23 mark (logic 1)	fV1		1280	1300	1320	Hz
frequency
ITU-T V.23 space (logic 0)	fV0		2068	2100	2132	Hz
frequency
Signal-to-noise ratio	SNR		20	–	–	dB
Band-pass filter gain ∗1	GBPF	300Hz	–	9.2	–	dB
		1200Hz	–	42.7	–	dB
		1700Hz	–	42.8	–	dB
		2200Hz	–	42.7	–	dB
		3000Hz	–	22.4	–	dB
		4000Hz	–	3.7	–	dB
		≥10000Hz	–	-20.0	–	dB
Carrier detection ON	CDON	VDD=5.0V	–	-51	-48	dBm
sensitivity ∗2
Carrier detection OFF	CDOFF	VDD=5.0V	-57	-54	–	dBm
sensitivity ∗2
Input clock frequency	fCLK		-0.1%	3.579545	+0.1%	MHz
Input AC impedance	RIN	VDD=5.0V (between TIP/RING pin and VREF)	70	100	130	kΩ
FSKON set-up time	tSUP		20	–	–	ms
Carrier detection response	tCDON		3	6.25	9	ms
time	tCDOFF		5	7.5	10	ms

∗1 Value measured between TIP/RING pin and BPOUT pin

∗2 The following expressions can be used to calculate the typical values (dBm) of CDON and CDOFF when an external resistor

RTR (10kΩ Typ.) is connected in series with the TIP pin and the RING pin.
CDON = -51 + 20log( VDD ⋅	100k	) [dBm] CDOFF = -54 + 20log(VDD ⋅	100k	) [dBm]
	RTR + 100k
5		5	RTR + 100k

In addition, the following expressions can be used to calculate the sensitivity of CDON and CDOFF when an external feedback resistor is used for the input amplifier (mask option).

GAmp = R5 = R6 (R1 = R2, R3 = R4, R5 = R6, see Figure 4.15.2.2.)

R1 R2

CDON = -51 + 20log( VDD ⋅	R1	) [dBm]	CDOFF = -54 + 20log(VDD ⋅	R1	) [dBm]
5	R5		5	R5

Band-pass filter gain (Typ. value)

	50
	40
	30
	20
(dB)	10
	0
Gain
	-10
	-20
	-30
	-40
	-50

0 1000 2000 3000

Frequency (Hz)

Timing chart

1st RING		2nd RING
Input	101010... 1	DATA
RDRC
RDET
FSKON	tSUP
CDET	tCDON	tCDOFF
FSKIN	101010... 1	DATA

4000

S1C63558 TECHNICAL MANUAL EPSON 165