U3761MB-T Datasheet, PDF (25/27 Pages) ATMEL Corporation – Universal Telephone IC - All Functions Integrated

U3761MB-T
Equations for
Electrical
Characteristic
Parameters of the
Speech Circuit
The equations refer to the basic test circuit. If not otherwise specified, the switches in
the basic test circuit are inactive.
Transmit Gain
GS
=
20
´
log
æ
è
V^----V-_M^---L-_I^-_C^--øö
V_MIC = 3 mV/1 kHz, S5 = open
Line-loss Compensation Transmit
DGS = GS (at I_L = 73 mA) - GS (at I_L = 20 mA)
TX-mode: V_MIC = 3 mV/1 kHz, S5 = open
Line-loss Compensation Receive
DGR = GR (at I_L = 73 mA) - GR (at I_L = 20 mA)
RX-mode: V_gen = 300 mV/1 kHz, S7b
Receiving Gain
GR = 20 ´ log_èæ^V-----^R-_V--^E--_L-^C---^O---_øö
RX-mode: V_gen = 300 mV/1 kHz, S7b
Sidetone Reduction
GSTA
=
20
´
log
æ
è
V^-----_R^-V--_E^--L-_C^----_O^--øö
(in TX-mode) + GR
TX-mode: V_MIC = 3 mV/1 kHz, S5 = open
Input Impedance of Microphone Amplifier
Ri = --------------------⁵---⁰-----^k--------------------
æ
è
V_{-----L--(--S---6----=----c--l-o---s--e---d--)}
V_{L(S6 = open)}
–
1_øö
TX-mode: VMIC = 3 mV/1 kHz, S5 = open
Gain Change when Muted
GRM
=
20
´
log
æ
è
V_{-----R-V--E--L-C----O--øö}
(Mute = inactive) -
20 ´ log_èæ^V-----^R-_V--^E--_L-^C----^O--_øö
(Mute = active)
V_gen = 100 mV/1 kHz, S5 = open, S8 = open
Total Harmonic Distortion (THD)
THD
=
20
´
æ
log_çç
è
-----ⁿ---¹----^´-----^U-----^L--^G----²----+-----ⁿ----¹----^´-----^U----^H----^G---²-----+----ⁿ----²----^´-----^U--_U---^L--_LG---_G-²--₂--+---+--ⁿ--_U--²---_H-^´--_G--^U--₂---^H---^G----²----+-----^.--^.--^.-ⁿ----ⁿ----^´-----^U----^L---^G----²----+-----ⁿ---ⁿ----^´-----^U-----^H---^G----²-_{ø÷÷ö}
n₁, ... n_n = harmonics of high and low frequency group
25
4744A–CORD–09/03