MX828 查看數據表（PDF） - MX-COM Inc
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MX828 Datasheet PDF : 34 Pages
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CTCSS/DCS/SelCall Processor
14
MX828 PRELIMINARY INFORMATION
4.4.11 RX TONE PROGRAM Register (Hex address $84)
This is a 16-bit register. Byte (1) is sent first. The two bytes are used to program the center frequencies of up to 15 tones
in either the audio or sub-audio band that will be decoded by the receiver.
Each tone is identified by its address in bits 7, 6, 5 and 4 of byte (1). The remaining 12 bits contain the data representing
the tone frequency according to the formula below. If a tone is not required the 12 bits should be set to zero.
Byte 1
Byte 2
Bit Bit Bit Bit Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
7 65 4
3
2
1
0
7
6
5
4
3
2
1
0
0 0 0 0 <------------------------ N -----------------------> <----------------------- R ------------------------>
0001
0 0 1 0 N is the binary representation of the
R is the nearest 6-bit binary
0 0 1 1 following decimal number (n):
representation of (r), where:
0100
0101
0110
0 1 1 1 SUBAUDIO (CTCSS)
SUBAUDIO (CTCSS)
1 0 0 0 n = INT (948982 x fTONE / fXTAL)
1001
r = ((237245/fXTAL) - (n/(4 x fTONE))) x 8400
1010
1011
1 1 0 0 INBAND (SELCALL)
1 1 0 1 n = INT (83036 x fTONE / fXTAL)
1110
INBAND (SELCALL)
r = ((20759/fXTAL) - (n/(4 x fTONE))) x 96000
Table 13: RX TONE PROGRAM Register (Hex address $84)
Example: To program 100Hz when using the recommended 4.032MHz Xtal in SUBAUDIO (CTCSS) mode.
n = INT (948982 x 100 / 4.032 x 10^6)
= INT (23.536) = 23
N = 010111 (binary)
r = ((237245 / 4.032 x 106) - (23 / (4 x 100))) x 8400
= 11.26
R = 11 (rounding up if exactly halfway)
= 001011 (binary)
Thus the 12-bit code is 010111001011
The Hex address represented by bits 7, 6, 5 and 4 in byte (1) is used as the code to indicate which tone has been
decoded. This code appears in bits 3, 2, 1 and 0 of the SELCALL and SUB-AUDIO STATUS Register (Hex address $81).
The 15 programmed tones use Hex addresses $0 - $E.
© 1997 MX•COM Inc.
www.mxcom.com Tele: 800 638-5577 336 744-5050 Fax: 336 744-5054
Doc. # 20480161.002
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
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