tda9874aps NXP Semiconductors, tda9874aps Datasheet - Page 25

• Manufacturer Part Number: tda9874aps
• Description: Digital Tv Sound Demodulator/decoder
• Manufacturer: NXP Semiconductors

Philips Semiconductors
7.3.5
This register should not be used when applying ESP.
Three bytes are required to define a 24-bit frequency
control word to represent the sound carrier (i.e. mixer)
frequency. These three bytes are stored at
subaddresses 3 to 5; subaddress 3 being the high byte.
Execution of the command starts only after all bytes have
been received. If an error occurs, e.g. a premature STOP
condition, partial data for this function is ignored. The
relation of the sound carrier frequency and the control
word is given in the following formula:
Table 21 Carrier 1 frequency register high byte (subaddress 3)
Table 22 Carrier 1 frequency register middle byte (subaddress 4)
Table 23 Carrier 1 frequency register low byte (subaddress 5)
7.3.6
This register should not be used when applying ESP. The
format is the same as for sound carrier 1, except
subaddresses 6 to 8 are used. Subaddress 6 holds the
high byte.
2000 Aug 04
data
Digital TV sound demodulator/decoder
=
B7
B7
B7
7
7
7
f
--------
f
C
mix
C
clk
ARRIER
ARRIER
2
24
1
2
FREQUENCY REGISTER
FREQUENCY REGISTER
B6
B6
B6
6
6
6
B5
B5
B5
5
5
5
B4
B4
B4
4
4
4
25
where:
Example: A 5.5 MHz sound carrier frequency will be
generated by sending the following sequence of data
bytes to the TDA9874A (data = 7509333 in decimal
notation or 729555 in hexadecimal notation):
0111 0010 1001 0101 0101 0101.
The default setting after Power-on reset is 0000 0000 for
all three bytes.
If this register is used, it will be for either the second
FM sound carrier of a terrestrial or satellite FM program or
for the NICAM sound carrier.
data = 24-bit frequency control word
f
f
2
mix
clk
24
B3
B3
B3
3
3
3
= 12288 MHz (clock frequency of mixer)
= 16777216 (number of steps in a 24-bit word size).
= desired sound carrier frequency
B2
B2
B2
2
2
2
B1
B1
B1
1
1
1
Product specification
TDA9874A
B0
B0
B0
0
0
0