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参数资料
| 型号： | AD6623 |
| 厂商： | Analog Devices, Inc. |
| 英文描述： | 4-Channel, 104 MSPS Digital Transmit Signal Processor TSP |
| 中文描述： | 4通道，104 MSPS的数字传输信号处理器判刑 |
| 文件页数： | 37/40页 |
| 文件大小： | 381K |
| 代理商： | AD6623 |
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REV. 0
AD6623
–37–
Time Restriction CMEM Restriction
N
L
RCF
RCF
≤
×
min
1
2
,16
256
(31)
DMEM Restriction
where:
L
L
L
L
M
N
f
f
RCF
CIC
CIC
CIC
TSP
CLK
IN
=
×
×
=
×
5
2
2
(32)
De-interleaving the input data into multiple TSPs extends the
time restriction and may possibly extend the DMEM restriction,
but will not extend the CMEM restriction. Deinterleaving the
input stream to multiple TSPs divides the input sample rate to
each TSP by the number of TSPs used (N
TSP
). To keep the output
rate fixed, L must be increased by a factor of N
CH
, which extends
the time restriction. This increase in L may be achieved by increas-
ing
any one or more of L
RCF
, L
CIC5
, or L
CIC2
within their normal
limits. Achieving a larger L by increasing L
RCF
instead of L
CIC5
or L
CIC2
will relieves the DMEM restriction as well.
In a UMTS example, N
TSP
= 4, f
CLK
= 76.8 MHz, and f
IN
=
3.84 MHz, resulting in L = 80. Factoring L into L
RCF
= 10,
L
CIC
= 8, and L
CIC2
= 1 results in a maximum N
RCF
= 40 due to
the time restriction. Figure 37 shows an example RCF impulse
response which has a frequency response as shown in Figure 38
from 0 Hz to 7.68 MHz (f
IN
L
RCF
/N
TSP
). The composite RCF
and CIC frequency response is shown in Figure 38, on the same
frequency scale. This figure demonstrates a good approximation
to a root-raised-cosine with a roll-off factor of 0.22, a passband
ripple of 0.1 dB, and a stopband ripple better than
–
70 dB until
the lobe of the first image which peaks at
–
60 dB about 7.68 MHz
from the carrier center. This lobe could be reduced by shifting
more of the interpolation towards the RCF, but that would
sacrifice near in performance. As shown, the first image can be
easily rejected by an analog filter further up the signal path.
Scaling must be considered as normal with an interpolation
factor of L, to guarantee no overflow in the RCF, CIC, or NCOs.
The output level at the summation port should be calculated
using an interpolation factor of L/N
TSP
.
Programming Multiple TSPs
Configuring the TSPs for de-interleaved operation is straight
forward. All the Channel Registers and the CMEM of each TSP
are programmed identically, except the Start Hold-Off Counters
and NCO Phase Offset.
In order to separate the input timing to each TSP, the Hold-Off
Counters must be used to start each TSP successively in response
to a common Start SYNC. The Start SYNC may originate from
the SYNC pin or the MicroPort. Each subsequent TSP must have
a Hold-Off Counter value L/N
TSP
larger than its predecessor
’
s.
If the TSPs are located on cascaded
AD6623s, the Hold-Off
Counters of the upstream device should
be incremented by an
additional one.
In the UMTS example, L = 80 and N
TSP
= 4, so to respond as
quickly as possible to a Start SYNC, the Hold-Off Counter
values should be 1, 21, 41, and 61.
Driving Multiple TSP Serial Ports
When configured properly, the AD6623 will drive each SDFO
out of phase. Each new piece of data should be driven only into
the TSP that pulses its SDFO pin at that time.
In the UMTS example in Figure 35, L = 80 and N
TSP
= 4, so
each serial port need only accept every fourth input sample.
Each serial port is shifting at peak capacity, so sample 1, 2, and
3 begin shifting into Serial Ports B, C, and D before sample 0 is
completed into Serial Port A.
SDFOA
SDFOB
SDFOC
SDFOD
0
4
1
5
2
7
6
3
Figure 35. UMTS Example
RAM
COEF
FILTER
CIC
NCO
SUMMATION
BLOCK
CIC
NCO
CIC
NCO
CIC
NCO
DATA
RE-FORMATTER
DAC
RAM
COEF
FILTER
RAM
COEF
FILTER
RAM
COEF
FILTER
76.8 MSAMPLES/SEC
76.8MSPS
76.8MSPS
76.8MSPS
76.8MSPS
9.6MSPS
9.6MSPS
9.6MSPS
9.6MSPS
0.96
MCPS
0.96
MCPS
0.96
MCPS
0.96
MCPS
3.84 MCPS
32
32
32
32
32
I
Q
I
Q
I
Q
I
Q
COMLEX SIGNAL 32 BITS (16, I, 16 Q)
REAL OR IMAGINARY SIGNAL
Figure 36. Summation Block
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相关代理商/技术参数 |
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|---|---|
| AD6623ABC | 制造商:Analog Devices 功能描述:Signal Processor 196-Pin CSP-BGA 制造商:Rochester Electronics LLC 功能描述:4 CHANNEL, 104 MSPS DIGITAL TSP - Bulk |
| AD6623ABCZ | 制造商:Analog Devices 功能描述:Signal Processor 196-Pin CSP-BGA |
| AD6623AS | 制造商:Analog Devices 功能描述:Signal Processor 128-Pin MQFP 制造商:Rochester Electronics LLC 功能描述:4 CHANNEL, 104 MSPS DIGITAL TSP - Bulk |
| AD6623ASZ | 功能描述:IC TSP 4CHAN 104MSPS 128MQFP RoHS:是 类别:集成电路 (IC) >> 接口 - 专用 系列:- 特色产品:NXP - I2C Interface 标准包装:1 系列:- 应用:2 通道 I²C 多路复用器 接口:I²C，SM 总线 电源电压:2.3 V ~ 5.5 V 封装/外壳:16-TSSOP（0.173"，4.40mm 宽） 供应商设备封装:16-TSSOP 包装:剪切带 (CT) 安装类型:表面贴装 产品目录页面:825 (CN2011-ZH PDF) 其它名称:568-1854-1 |
| AD6623BC/PCB | 制造商:AD 制造商全称:Analog Devices 功能描述:4-Channel, 104 MSPS Digital Transmit Signal Processor TSP |
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