TrueSpeech® Co-Processor
PRELIMINARY/CONFIDENTIAL
Version: 1.18
9.20.6
Selecting the Filter Characteristics
The CT8022 includes Filter Parameter Sets for eight different call progress tone (CPT) fixed filters plus an
additional set of four Filter Parameters that may be programmed by the Host. Each of the four filters F0-F1 can be
mapped onto any of the twelve available filter parameter sets. The first four filter parameter sets are stored in the
CT8022s internal RAM and may be re-programmed by the Host.
Filters
Mapping Table
Filter Set
Filter F0
Filter F1
Filter F2
Filter F3
2
10
9
Programmable Set 0
Programmable Set 1
Programmable Set 2
Programmable Set 3
11
Fixed Set 4
Fixed Set 5
Fixed Set 6
Fixed Set 7
Fixed Set 8
Fixed Set 9
Fixed Set 10
Fixed Set 11
Figure 9-5:
Filter Mapping
The following table shows the default contents of the Filter Parameter Sets:
Filter Parameter Set
0
1
2
3
4
5
6
7
Programmable Filter Set 0 (by default this is loaded with Fixed Set 4)
Programmable Filter Set 1 (by default this is loaded with Fixed Set 5)
Programmable Filter Set 2 (by default this is loaded with Fixed Set 6)
Programmable Filter Set 3 (by default this is loaded with Fixed Set 7)
Fixed Filter Set 4 (wide CPT filter 300Hz - 640 Hz)
Fixed Filter Set 5 (narrow CPT filter 300Hz - 500 Hz)
Fixed Filter Set 6 (fax calling tone CNG 1100Hz +/- 5%)
Fixed Filter Set 7 (350 Hz +/- 5%)
8
Fixed Filter Set 8 (400 Hz +/- 5%)
9
Fixed Filter Set 9 (480 Hz +/- 5%)
10
11
Fixed Filter Set 10 (440 Hz +/- 5%)
Fixed Filter Set 11 (620 Hz +/- 5%)
The Host may program the Filter Parameter Set used by each of the Filters F0-F3. The filter set used by each filter is
controlled by the CT8022’s Filter Parameter Set Mapping Table. The default Filter Set selection is shown below:
134
DSP GROUP, INC., 3120 SCOTT BOULEVARD CT8022A11AQC FW Revision 0118
SANTA CLARA, CA 95054 PH: 408 986 – 4300 FAX: 408 986 – 4490
All specifications are subject to change without prior notice.
ETC [ ETC ]
