tda9870ah NXP Semiconductors, tda9870ah Datasheet - Page 37

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tda9870ah

Manufacturer Part Number
tda9870ah
Description
Digital Tv Sound Processor Dtvsp
Manufacturer
NXP Semiconductors
Datasheet
Philips Semiconductors
10.3.4
The three bytes together constitute a 24-bit frequency
control word to represent the sound carrier (i.e. mixer)
frequency in accordance with the following formula:
Where:
Example: A 5.5 MHz sound carrier frequency will be
generated by sending the following sequence of data
bytes to the TDA9870A (data = 7509333 in decimal
notation or 729555 in hexadecimal):
01110010 10010101 01010101.
As three bytes are required to define a carrier frequency,
execution of this 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 default setting at power-up is 00000000 for all three
bytes.
Most significant part at subaddress 3 and least significant
part at subaddress 5 (see Table 19).
1999 Dec 20
data
data = 24-bit frequency control word
f
f
2
Digital TV Sound Processor (DTVSP)
mix
clk
24
= 12.288 MHz (clock frequency of mixer)
=
= 16777216 (number of steps in a 24-bit word size).
= desired sound carrier frequency
f
-------- -
f
C
mix
clk
ARRIER
2
24
1
FREQUENCY REGISTER
37
Table 19 Subaddresses 3 to 5
ADDRESS
SUB-
3
4
5
7 (MSB)
0 (LSB)
BIT
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
carrier 1 frequency;
most significant part
carrier 1 frequency
carrier 1 frequency;
least significant part
DESCRIPTION
Product specification
TDA9870A

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