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參數(shù)資料
| 型號： | EVAL-AD7760EDZ |
| 廠商： | Analog Devices Inc |
| 文件頁數(shù)： | 26/37頁 |
| 文件大?。?/td> | 0K |
| 描述： | BOARD EVAL CONTROL AD7760 |
| 標(biāo)準(zhǔn)包裝： | 1 |
| ADC 的數(shù)量： | 1 |
| 位數(shù)： | 24 |
| 采樣率（每秒）： | 2.5M |
| 數(shù)據(jù)接口： | 并聯(lián) |
| 輸入范圍： | ±3.25 Vpp |
| 在以下條件下的電源（標(biāo)準(zhǔn)）： | 958mW @ 2.5MSPS |
| 工作溫度： | -40°C ~ 85°C |
| 已用 IC / 零件： | AD7760 |
| 已供物品： | 板，CD |
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AD7760
Rev. A | Page 31 of 36
DOWNLOADING A USER-DEFINED FILTER
As previously mentioned, the filter coefficients are 27 bits in
length—one sign and 26 magnitude bits. Because the AD7760
has a 16-bit parallel bus, the coefficients are padded with 5 MSB
0s to generate a 32-bit word, split into two 16-bit words for
downloading. The first 16-bit word for each coefficient becomes
(00000, sign bit, Magnitude [25:16]), whereas the second word
becomes (Magnitude [15:0]). To ensure that a filter is downloaded
correctly, a checksum must also be generated and then downloaded
following the final coefficient. The checksum is a 16-bit word
generated by splitting each 32-bit word into four bytes and
summing the bytes from all coefficients up to a maximum of
192 bytes (48 coefficients × four bytes). The same checksum
is generated internally in the AD7760 and compared with the
downloaded checksum. The DL_OK bit in the status register is
set if these two checksums agree.
To download a user filter
1.
Write to Control Register 1, setting the DL_FILT bit and
the correct filter length bits corresponding to the length of
the filter to be downloaded (see Table 11).
2.
Write the first half of the current coefficient data
(00000, sign bit, Magnitude [25:16]). The first coefficient
to be written must be the one adjacent to the point of filter
symmetry.
3.
Write the second half of the current coefficient data
(Magnitude [15:0]).
4.
Repeat Step 2 and Step 3 for each coefficient.
5.
Write the 16-bit checksum.
6.
Use the following methods to verify that the filter coefficients
are downloaded correctly:
a.
Read the status register, checking the DL_OK bit.
b.
Read data and observe the status of the DL_OK bit.
Note that because the user coefficients are stored in RAM, they
are cleared after a RESET operation or a loss of power.
Table 11. Filter Length Values
FLEN [3:0]
Number of Coefficients
Filter Length
0000
Default
0001
6
12
0011
12
24
0101
18
36
0111
24
48
1001
30
60
1011
36
72
1101
42
84
1111
48
96
EXAMPLE FILTER DOWNLOAD
The following is an example of downloading a short user-
defined filter with 24 taps. The frequency response is shown in
10
–80
06
FREQUENCY (kHz)
A
M
P
L
IT
UDE
(
d
B)
00
0
–10
–20
–30
–40
–50
–60
–70
100
200
300
400
500
04
97
5-
04
5
Figure 58. 24-Tap FIR Frequency Response
The coefficients for the filter are listed in Table 12 and are
shown from the center of symmetry outwards. The raw
coefficients were generated using a commercial filter design
tool and were scaled appropriately so that their sum equals
67,108,863 (0x3FF FFFF).
Table 12. 24-Tap FIR Coefficients
Coefficient
Raw
Scaled
1
0.365481974
53188232
2
0.201339905
29300796
3
0.009636604
1402406
4
0.075708848
11017834
5
0.042856209
6236822
6
0.019944246
2902466
7
0.036437914
5302774
8
0.007592007
1104856
9
0.021556583
3137108
10
0.024888355
3621978
11
0.012379538
1801582
12
0.001905756
277343
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| EVAL-AD7762EB | 制造商:Analog Devices 功能描述:EVALUATION CONTROL BOARD I.C. - Bulk |
| EVAL-AD7762EBZ | 制造商:Analog Devices 功能描述:EVALUATION CONTROL BOARD I.C. - Bulk |
| EVAL-AD7762EDZ | 功能描述:BOARD EVAL CONTROL AD7762 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - 模數(shù)轉(zhuǎn)換器 (ADC) 系列:- 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:- ADC 的數(shù)量:1 位數(shù):12 采樣率（每秒）:94.4k 數(shù)據(jù)接口:USB 輸入范圍:±VREF/2 在以下條件下的電源（標(biāo)準(zhǔn)）:- 工作溫度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板，軟件 |
| EVAL-AD7763EB | 制造商:Analog Devices 功能描述:EVALUATION BOARD I.C. - Bulk |
| EVAL-AD7763EBZ | 制造商:Analog Devices 功能描述:EVALUATION BOARD I.C. - Bulk |
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