TS5070 Datasheet, PDF (12/32 Pages) STMicroelectronics – PROGRAMMABLE CODEC/FILTER COMBO 2ND GENERATION

TS5070 - TS5071
Table 8: Byte 2 of Receive Gain Instructions.
Bit Number
76543210
00000000
00000001
00000010
10101110
11110011
11111010
11111111
0dBm0 Test Leve at VF_R0
In dBm (Into 600Ω)
In Vrms (approx.)
No Output
– 17.3
– 17.2
0.106
0.107
0
0.775
+ 6.9 (note 1)
1.71
+ 7.6 (note 2)
1.86
+ 8.1 (note 3)
1.07
Notes:
1. Maximum level into 300Ω ; 2. Maximum level into 600Ω; 3. RL ≥15KΩ (*) State at power on initialization
HYBRID BALANCE FILTER
attenuator.
The Hybrid Balance Filter on COMBO IIG is a
programmable filter consisting of a second-order
Bi-Quad section, Hybal1, followed by a first-order
section, Hybal2, and a programmable attenuator.
Either of the filter sections can be bypassed if
only one is required to achieve good cancellation.
A selectable 180 degree inverting stage is in-
cluded to compensate for interface circuits which
also invert the transmit input relative to the re-
ceive output signal. The Bi-Quad is intended
The Bi-Quad mode of Hybal1 is most suitable for
balancing interfaces with transformers having high
inductance of 1.5 Henries or more. An alternative
configuration for smaller transformers is available
by converting Hybal1 to a simple first-order section
with a single real low frequency pole and 0 Hz zero.
In this mode, the pole/zero frequency may be pro-
grammed.
Many line interfaces can be adequately balanced
by use of the Hybal1 section only, in which case
mainly to balance low frequency signals across a the Hybal2 filter should be de-selected to bypass
transformer SLIC, and the first order section to
balance midrange to higher audio frequency sig-
nals. The attenuator can be programmed to com-
pensate for VFRO to VFXI echos in the range
of -2.5 to – 8.5 dB.
it.
Hybal2, the higher frequency first-order section, is
provided for balancing an electronic SLIC, and is
also helpful with a transformer SLIC in providing
additional phase correction for mid and high-band
As a Bi-Quad, Hybal1 has a pair of low frequency
zeroes and a pair of complex conjugate poles.
When configuring the Bi-Quad, matching the
phase of the hybrid at low to midband frequencies
is most critical. Once the echo path is correctly
balanced in phase, the magnitude of the cancella-
tion signal can be corrected by the programmable
frequencies, typically 1 kHz to 3.4 kHz. Such a
correction is particularly useful if the test balance
impedance includes a capacitor of 100 nF or less,
such as the loaded and non-loaded loop test net-
works in the United States. Independent place-
ment of the pole and zero location is provided.
Table 9: Hybrid Balance Register 1 Byte 2 Instruction.
Bit
State
Function
7
0
Disable Hybrid Balance Circuit Completely.
No internal cancellation is provided. ^*
1
Enable Hybrid Balance Cancellation Path
6
0
Phase of the internal cancellation signal assumes inverted phase of the echo
path from VF_RO to VF_XI.
1
Phase of the internal cancellation signal assumes no phase inversion in the line
interface.
5
0
Bypass Hybal 2 Filter Section
1
Enable Hybal 2 Filter Section
G4–G0
Attenuation Adjustment for the Magnitude of the Cancellation Signal. Range is
– 2.5 dB (00000) to – 8.5 dB (11000)
(*) State at power on initialization
Setting = Please refer to software TS5077 2
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