AMBE-1000 Digital Voice Systems, Inc., AMBE-1000 Datasheet - Page 34

• Manufacturer Part Number: AMBE-1000
• Manufacturer: Digital Voice Systems, Inc.

4.1.5
4.1.6
Signal to Noise
Distortion ratio
Tone Duration
Reverse Twist
Requirement
Normal Twist
Input Level
DTMF Tone
Frequency
Frequency
Tolerance
Maximum
Tolerance
Detection
Minimum
Minimum
Minimum
Minimum
Range
Range
The AMBE-1000 is not recommended for new designs.
Please refer to the AMBE-2000/2020 product line.
Framed Output : Status_1
Framed Output : Status_2
Table 4-C DTMF Tone Detection Parameters
This 16 bit field is unused and is output as 0x0000.
This 16 bit field is used only when a DTMF tone is detected. If the DTMF Detected Flag
is set in Status_0, then the DTMF Code and DTMF Amplitude fields in Status_2 will be
filled according to Table 4-D and Table 4-E.
Table 4-D Status_2 Format
DTMF Code
-25 dBm0
8-10 dB
4-10 dB
Bits 15:8
45 mS
15 dB
Value
1.5%
3.5%
The AMBE-1000 is not recommended for new designs.
Please refer to the AMBE-2000/2020 product line.
Description
An input signal shall not be rejected as a DTMF tone if its amplitude is greater
than -25 dBm0 (maximum sinusoid dBm0 is defined as+3.17 dBm0).
In order for an input signal to correspond to a valid DTMF tone, the ratio of
inband to out-of-band energy must be greater than 15dB.
defined to be the energy in frequency components within
frequencies defined by the DTMF frequencies. Out-of-band energy is defined to
be the total energy minus in the inband energy.
An input signal shall not be rejected as a DTMF tone if both of its principal
frequency components are within 1.5% of the frequencies needed for the DTMF
tone.
An input signal shall not be rejected as a DTMF tone if either of its principal
frequency components are outside 3.5% of the frequencies needed for the DTMF
tone.
An input signal does not correspond to a valid DTMF tone if the energy contained
within the low frequency band is more than 10 dB greater than the energy
contained in the high frequency band. An input signal shall not be rejected as a
DTMF if energy contained within the low frequency band is less than 8 dB greater
than the energy contained in the high frequency band.
frequency band is limited to 3.5% of the frequencies needed for the DTMF tone.
An input signal does not correspond to a valid DTMF tone if the energy contained
within the high frequency band is more than 10 dB greater than the energy
contained in the low frequency band. An input signal shall not be rejected as a
DTMF if energy contained within the high frequency band is less than 4 dB
greater than the energy contained in the low frequency band. Each low and high
frequency band is limited to 3.5% of the frequencies needed for the DTMF tone.
An input signal shall not be rejected as a DTMF tone as long as its time duration
is greater than 45 mS. In addition a minimum of two frames will be transmitted
of the DTMF tone if a valid tone is detected. The duration of a tone is defined by
the points at which the envelope is 20 dB below its peak value.
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Status_2 (see Table 4-A)
page 34
DTMF Amplitude
Bits 7:0
Each low and high
Inband energy is
3.5% of the two