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參數資料
| 型號： | AD9864 |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | IF Digitizing Subsystem |
| 中文描述： | 中頻數字化子系統 |
| 文件頁數： | 21/44頁 |
| 文件大小： | 1984K |
| 代理商： | AD9864 |
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AD9864
Table 9. Number of Bits per Frame for Different SSICR Settings
DW
EAGC
EFS
0 (16 Bit)
0
0
0
1
1
0
1
0
1
1
1
1
1 (24 Bit)
0
0
0
1
1
0
1
0
1
1
1
1
*The number of bits per frame with embedded frame sync (EFS = 1); assume
at least 10 idle bits are desired.
The maximum SSIORD setting can be determined by the
equation
(
Factor
Decimation
TRUNC
SSIORD
≤
Rev. 0 | Page 21 of 44
AAGC
NA
NA
0
1
0
1
NA
NA
0
1
0
1
Number
of Bits
per
Frame
32
49*
48
40
69*
59*
48
69*
64
56
89*
79*
) (
/
)
[
]
Frame
per
Bits
of
No.
(1)
where
TRUNC
is the truncated integer value.
Table 9 lists the number of bits within a frame for 16-bit and 24-
bit output data formats for all of the different SSICR settings. The
decimation factor is determined by the contents of Register 0x07.
An example helps illustrate how the maximum SSIORD setting
is determined. Suppose a user selects a decimation factor of 600
(Register 0x07, K = 0, M = 9) and prefers a 3-wire interface with
a dedicated frame sync (EFS = 0) containing 24-bit data
(DW = 1) with nonalternating embedded AGC data included
(EAGC = 1, AAGC = 0). Referring to Table 9, each frame will
consist of 64 data bits. Using Equation 1, the maximum
SSIORD setting is 9 (=
TRUNC
(600/64)). Thus, the user can
select any SSIORD setting between 1 and 9.
Figure 32
illustrates the output timing of the SSI port for several
SSI control register settings with 16-bit I/Q data, while Figure 33
shows the associated timing parameters. Note that the same
timing relationship holds for 24-bit I/Q data, with the excep-
tion that I and Q word lengths now become 24 bits. In the
default mode of operation, data is shifted out on rising edges of
CLKOUT after a pulse equal to a clock period is output from
the frame sync (FS) pin. As described above, the output data
consists of a 16-bit or 24-bit I sample followed by a 16-bit or
24-bit Q sample, plus two optional bytes containing AGC and
status information.
I15
I14
t
CLK
t
HI
t
V
t
DV
t
LOW
CLKOUT
FS
DOUT
0
Figure 33. SSI Timing Parameters for SSI Timing*
*Timing parameters also apply to inverted CLKOUT or FS modes, with t
DV
relative to the falling edge of the CLK and/or FS.
The AD9864 also provides the means for controlling the
switching characteristics of the digital output signals via the DS
(drive strength) field of the SSICRB. This feature is useful in
limiting switching transients and noise from the digital output
that may ultimately couple back into the analog signal path,
potentially degrading the AD9864’s sensitivity performance.
Figure 34 and Figure 35 show how the NF can vary as a func-
tion of the SSI setting for an IF frequency of 109.65 MHz. The
following two observations can be made from these figures:
1. The NF becomes more sensitive to the SSI output drive
strength level at higher signal bandwidth settings.
2.
The NF is dependent on the number of bits within an SSI
frame that become more sensitive to the SSI output drive
strength level as the number of bits is increased. As a result,
one should select the lowest possible SSI drive strength set-
ting that still meets the SSI timing requirements.
SSI OUTPUT DRIVE STRENGTH SETTING
2
10.0
4
N
9.6
3
1
8.0
7
6
5
24-BIT I/O DATA
9.8
9.4
9.2
9.0
8.6
8.8
8.4
8.2
16-BIT I/0 DATA
w/ DVGA ENABLED
16-BIT I/O DATA
0
Figure 34. NF vs. SSI Output Drive Strength
(VDDx = 3.0 V, F
CLK
= 18 MSPS, BW = 10 kHz)
相關PDF資料 |
PDF描述 |
|---|---|
| AD9864-EB | IF Digitizing Subsystem |
| AD9864BCPZ | IF Digitizing Subsystem |
| AD9864BCPZRL | IF Digitizing Subsystem |
| AD9866BCPRL | Broadband Modem Mixed Signal Front End |
| AD9866CHIPS | Broadband Modem Mixed Signal Front End |
相關代理商/技術參數 |
參數描述 |
|---|---|
| AD9864BCP | 制造商:Analog Devices 功能描述:IF SUBSYS 48LFCSP EP - Bulk |
| AD9864BCPZ | 功能描述:IC IF SUBSYSTEM GEN-PURP 48LFCSP RoHS:是 類別:RF/IF 和 RFID >> RF 前端 (LNA + PA) 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:250 系列:- RF 型:GPS 頻率:1575.42MHz 特點:- 封裝/外殼:48-TQFP 裸露焊盤 供應商設備封裝:48-TQFP 裸露焊盤（7x7） 包裝:托盤 |
| AD9864BCPZ | 制造商:Analog Devices 功能描述:IC, IF SUBSYSTEM, 16-24BIT, 6.8KHZ-270KH |
| AD9864BCPZRL | 功能描述:IC IF SUBSYSTEM GEN-PURP 48LFCSP RoHS:是 類別:RF/IF 和 RFID >> RF 前端 (LNA + PA) 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:250 系列:- RF 型:GPS 頻率:1575.42MHz 特點:- 封裝/外殼:48-TQFP 裸露焊盤 供應商設備封裝:48-TQFP 裸露焊盤（7x7） 包裝:托盤 |
| AD9864-EB | 制造商:Analog Devices 功能描述: |
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