Audio Signaling Processor
15
MX803A PRELIMINARY INFORMATION
1996 MX
COM, INC.
Tele: 800 638 5577 910 744 5050 Fax: 910 744 5054
Doc. # 20480122.003
5.2.5.2 Mid Band Measurement
S
IN
- MID Band
In the measurement period of 18.250ms, there are N cycles
at 2S
IN
and R clock cycles at 28.000kHz.
N and R - High Band
The measurement period = 18.250ms.
Clock Frequency = 28.000kHz
The measured frequency = 2S
IN
Hz
In the measurement period there are:
(
)
N
S
IN
2
from which S = 14000 x N
IN
+
R
28000 = 18.250ms
511 - R
2S
IN
x 18.250 x 10 cycles
N
MID
is the lower integer value of the decimal number:
N = INT (18.250 x 10 x 2S )
R
MID
is the lower integer value of the decimal number:
R = INT (18.250 x 10 -
N
2S
) x 28000
IN
5.2.5.3 Extended Band Measurement
S
IN
- Extended Band
In the measurement period of 9.125ms, there are N cycles
at 2S
IN
and R clock cycles at 56.000kHz.
N and R - High Band
The measurement period = 9.125ms.
Clock Frequency = 56.000kHz
The measured frequency = 2S
IN
Hz
In the measurement period there are:
(
)
N
S
IN
2
from which S = 28000 x N
IN
+
R
56000 = 9.125ms
511 - R
2S
IN
x 9.125 x 10 cycles
N
EXTENDED
is the lower integer value of the decimal number:
N = INT (9.125 x 10 x 2S )
R
EXTENDED
is the lower integer value of the decimal number:
R = INT (9.125 x 10 - 3 -
N
2S
) x 56000
IN
5.2.6 Write to RX Notone Timer Register
A/C 33
H
, followed by 1 byte of Command Data
5.2.6.1 Operation of the RX Notone Timer
A NOTONE period is that period when no signal or a consistently bad quality signal is received. The NOTONE Timer is
employed to indicate to the
μ
C that a NOTONE situation has existed for a predetermined period.
The NOTONE Timer period is “primed” by writing to the NOTONE Timer Register (33
H
) using the instructions and
information (1 data byte) given in Table 6. This timer register can be written-to and set in any mode of the MX803A
except “Notone Timer Powersave.” Priming the timer sets the timing period; this period will not be allowed to start until at
least one frequency (tone) measurement has been successfully completed.
The NOTONE Timer is a one-shot timer that is reset only by successful tone measurements.
If the quality of the received signal drops to an unusable level the NOTONE Timer will start its run-down. On completion
of this timer period, the NOTONE Timer Period Expired bit in the Status Register and an Interrupt are set.
Upon detection of the Interrupt, the Status Register should be read by the
μ
C to ascertain the source of the Interrupt.