Data Sheet
MT88E45B
a
b
c
Parameter
North America: Bellcore
Europe: ETSI
UK: BT
Mark (Logical 1) Frequency
Space (Logical 0) Frequency
Received Signal Level
1200 Hz +/- 1%
2200 Hz +/- 1%
1300 Hz +/- 1.5%
2100 Hz +/- 1.5%
e
-4.23 to -36.20 dBm
-5.78 to -33.78 dBm
-5.78 to -37.78 dBm
(-8 to -40 dBV)
d
f,g
(476 to 12 mVrms)
(-8 to -36 dBV)
Signal Reject Level
-48.24 dBm (3mVrms) for
On-hook No Ring Signalling
such as VMWI
On-hook only:
-47.78 dBm
(-50dBV)
Transmission Rate
1200 baud +/- 1%
-6 to +10 dB
1200 baud +/- 1%
-6 to +6 dB
Twist (VMARK/VSPACE
)
Signal to Noise Ratio
Single Tone (f):
-18 dB (f<=60Hz)
>= 25 dB
>= 20 dB
(300 to 3400 Hz)
(300 to 3400 Hz)
-12 dB (60<f<=120Hz)
-6 dB (120<f<=200Hz)
+25 dB (200<f<3200Hz)
+6 dB (f>=3200Hz)
h
Tip/Ring Op-Amp (GS1) Gain
Vdd = 5V +/- 10%
0 dB
-2 dB
0 dB
i
Tip/Ring Op-Amp (GS1) Gain
Vdd = 3V +/- 10%
-3.5 dB
-5.5 dB
-3.5 dB
a. ANSI/TIA/EIA-716 and TIA/EIA-777. Bellcore has agreed to the values and will synchronize its requirements.
b. ETS 300 778-1 (On-hook) Sep 97, ETS 300 778-2 (Off-hook) Jan 98.
c. SIN 227 Issue 3 Nov 97, SIN242 Issue 2 Nov 96.
d. North American on-hook signalling range. The off-hook range is inside the on-hook range: 190mVrms to 12mVrms.
e. dBm - Decibels above or below a reference power of 1 mW into 600 ohms. 0 dBm = 0.7746 Vrms
f. dBV - Decibels above or below a reference voltage of 1 Vrms. 0 dBV = 1 Vrms.
g. ETSI on-hook signalling range. The off-Hook signalling levels are inside this range: -8.78 to -30.78 dBm (-11 to -33 dBV).
h. The 5V ETSI Tip/Ring op-amp gain can be 0 dB if there is no FSK reject level requirement.
i. The 3V ETSI Tip/Ring op-amp gain can be -3.5dB if there is no FSK reject level requirement.
Table 4 - FSK Signal Characteristics
The MT88E45B is compliant with the Bellcore/TIA,
FSK Demodulation
ETSI and BT requirements with the Tip/Ring op-amp
The FSK characteristics are shown in Table 4. In
gains in Table 4. In Europe if the country specific
North America, TIA (Telecommunications Industry
FSK requirements do not incorporate ETSI’s FSK
Association) also sets standards. The Type 1 Caller
reject level then the Tip/Ring op-amp gain can also
ID CPE standard is ANSI/TIA/EIA-716. The Type 2
be 0dB at 5V and -3.5dB at 3V to meet the ETSI
standard is TIA/EIA-777. The North American FSK
minimum CAS level for on-hook signalling (-40 dBV).
characteristics in Table 4 are from ANSI/TIA/EIA-
716. They differ from those Bellcore published in SR-
For 3V operation, the FSK receiver becomes more
sensitive and lower level signals will be accepted
than at 5V. To maintain the FSK reject level, the Tip/
Ring input op-amp gain should be reduced. Note that
since the Tip/Ring op-amp is also used for Tip/Ring
CAS detection, the CAS level will also be reduced for
on-hook detection.
TSV-002476 and SR-3004. Bellcore is represented
in TR41.3.1 and will synchronize to the TIA
requirements in its future documents.
The TIA Type 1 standard includes an FSK reject
level:
•
if data is not preceded by ringing (e.g. VMWI),
FSK signals below 3mVrms (-48.24 dBm) shall
be rejected
FSK Data Interface
The MT88E45B provides a powerful dual mode 3-
wire interface so that the data bytes in the
demodulated FSK bit stream can be extracted
without the need either for an external UART or for
the CPE’s microcontroller to perform the function in
•
if data is preceded by ringing, FSK detection
may be extended below 3mVrms
9
ZARLINK [ ZARLINK SEMICONDUCTOR INC ]
