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DB839 Datasheet, PDF (11/20 Pages) CML Microcircuits – Two Variable Attenuators
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Digitally Controlled Analog I/O Processor
11
MX839 PRELIMINARY INFORMATION
4.7.3 VARIABLE ATTENUATOR Register (Hex address $D2)
This is a 16-bit register. Byte (1) is sent first. Bits 0 - 5 of the first byte in this register are used to enable and set the
attenuation of the Modulator 1 amplifier. Bits 0 - 5 of the second byte in this register are used to enable and set the
attenuation of the Modulator 2 amplifier. See Table 7.
543210
0XXXXX
100000
100001
100010
100011
100100
100101
100110
100111
101000
101001
101010
101011
101100
101101
101110
101111
110000
110001
110010
110011
110100
110101
110110
110111
111000
111001
111010
111011
111100
111101
111110
111111
X = don't care
MOD1 ENABLE
(Bit 5, first byte)
MOD2 ENABLE
(Bit 5, second byte)
(Bits 7 and 6, first
and second bytes)
Mod. 1 Attenuation
Disabled (VBIAS)
>40dB
12.0dB
11.6dB
11.2dB
10.8dB
10.4dB
10.0dB
9.6dB
9.2dB
8.8dB
8.4dB
8.0dB
7.6dB
7.2dB
6.8dB
6.4dB
6.0dB
5.6dB
5.2dB
4.8dB
4.4dB
4.0dB
3.6dB
3.2dB
2.8dB
2.4dB
2.0dB
1.6dB
1.2dB
0.8dB
0.4dB
0dB
543210
0XXXXX
100000
100001
100010
100011
100100
100101
100110
100111
101000
101001
101010
101011
101100
101101
101110
101111
110000
110001
110010
110011
110100
110101
110110
110111
111000
111001
111010
111011
111100
111101
111110
111111
Mod. 2 Attenuation
Disabled (VBIAS)
>40dB
6.0dB
5.8dB
5.6dB
5.4dB
5.2dB
5.0dB
4.8dB
4.6dB
4.4dB
4.2dB
4.0dB
3.8dB
3.6dB
3.4dB
3.2dB
3.0dB
2.8dB
2.6dB
2.4dB
2.2dB
2.0dB
1.8dB
1.6dB
1.4dB
1.2dB
1.0dB
0.8dB
0.6dB
0.4dB
0.2dB
0dB
When this bit is '1' the MOD1 attenuator is enabled.
When this bit is '0' the MOD1 attenuator is disabled (i.e. powersaved).
When this bit is '1' the MOD2 attenuator is enabled.
When this bit is '0' the MOD2 attenuator is disabled (i.e. powersaved).
Reserved for future use. These should be set to '0'.
Table 7: VARIABLE ATTENUATOR Register (Hex address $D2)
© 1998 MXxCOM Inc.
www.mxcom.com Tele: 800 638-5577 336 744-5050 Fax: 336 744-5054
Doc. # 20480164.002
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