U3761MB Datasheet, PDF (21/23 Pages) TEMIC Semiconductors – Low Voltage Standard Telephone Circuit with 13 Memories

U3761MB
Formulas for Parameters of Elecrtrical Characteristics of Speech Circuit
Formulas referred to the basic test circuit. If not otherwise specified switches in basic test circuit are inactive.
+ ^{ǒ Ǔ Transmit gain}
GS
20
log
VL
VMIC
VMIC = 3 mV/1 kHz, S5 = open
+ ^{ǒ Ǔ Receiving gain}
GR
20
log
VRECO
VL
RX-mode: VGEN = 300 mV/1 kHz, S7b
+ + + ^{Line loss compensation transmit}
DGS GS(at IL 73 mA)–GS(at IL 20 mA)
TX-mode: VMIC = 3 mV/1 kHz, S5 = open
+ ^{ǒ Ǔ} ) ^{Sidetone reduction}
GSTA
20
log
VL
VRECO
(in
TX–mode)
GR
TX-mode: VMIC = 3 mV/1 kHz, S5 = open
+ + + ^{Line loss compensation receive}
DGR GR(at IL 73 mA)–GR(at IL 20 mA)
RX-mode: VGEN = 300 mV/1 kHz, S7b
Gain change when muted
+ + GRM
20
log
VRECO
VL
(Mute
inactive)–20
VGEN = 100 mV/1 kHz, S5 = open, S8 = open
+ log
VRECO
VL
(Mute
active)
Input impedance of microphone amplifier
+ _{ǒ Ǔ} Ri
50 k
+ _–1 ^VL(s6 closed)
+ ^VL(S6 open)
TX-mode: VMIC = 3 mV/1 kHz, S5 = open
TELEFUNKEN Semiconductors
Rev. A2, 23-Apr-97
Preliminary Information
21 (23)