z02201 ZiLOG Semiconductor, z02201 Datasheet - Page 60

• Manufacturer Part Number: z02201
• Description: Z02201 V.22bis Data Pump With Integrated Afe
• Manufacturer: ZiLOG Semiconductor

Simultaneous Transmission and Detection of Tones
PS000904-0107
Setting CONFIG register, bits 0–6 (MODE) to
of all Discrete Tone Detectors, Biquad Tone Detectors, and Tone Generators.
Please refer to the sections
on page 51 for descriptions of how to use each of these features by itself.
The host uses simultaneous transmission and detection of tones when it needs to
detect tones while generating a single tone. An example during the call establish-
ment phase of a special purpose modem.
To prevent a single generated tone from interfering with the tone detectors the
host programs data pump RAM locations 0x1A2 through 0x1A6 with coefficients
for a notch filter to remove a single tone from the received signal used by the tone
detectors.
The notch filter coefficients are set to their default values when the host sets CON-
FIG register, bits 0–6 (MODE) to
after setting CONFIG register, bits 0–6 (MODE) to begin simultaneous transmission
and detection of tones. The default notch filter coefficient values cause the notch
filter to not change the received signal used by the tone detectors.
The notch filter is a biquad section (2nd-order IIR filter). The values of the coeffi-
cients determine the frequency to be removed. Refer to the description of RAM
location “Notch” for the formulae used to compute these commonly used coeffi-
cient values:
Table 24. Notch Filer Coefficients
f (Hz)
default
600
1300
1650
1750
1800
2100
2225
2250
0x1A2
0x0
0xCC2A
0xCC2A
0xCC2A
0xCC2A
0xCC2A
0xCC2A
0xCC2A
0xCC2A
0x1A3
0x0
0x6A6D
0x4BF4
0x364D
0x2F8A
0x2C15
0x1679
0x0D2A
0x0B4A
Transmitting Tones
4
, so the host writes new values to these locations
0x1A4
0x0
0x3DCD
0x3A89
0x3A34
0x3A24
0x3A1D
0x39FE
0x39F5
0x39F4
V.22BIS Data Pump with Integrated AFE
4
enables the simultaneous operation
0x1A5
0x0
0x8DCF
0xB2CF
0xC921
0xD002
0xD385
0xE95F
0xF2C1
0xF4A4
on page 50, and
0x1A6
0x3DCD
0x3A89
0x39F4
0x4000
0x3A34
0x3A24
0x3A1D
0x39FE
0x39F5
Tone Detectors
56