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参数资料
| 型号： | TMC2249AH5C |
| 厂商： | FAIRCHILD SEMICONDUCTOR CORP |
| 元件分类： | DSP Peripheral |
| 英文描述： | 12-BIT, DSP-MIXER, PPGA120 |
| 封装： | PLASTIC, PGA-120 |
| 文件页数： | 4/18页 |
| 文件大小： | 138K |
| 代理商： | TMC2249AH5C |
PRODUCT SPECIFICATION
TMC2249A
12
REV. 1.0.2 7/6/00
Complex Arithmetic Functions
The TMC2249A can also be used to perform complex arith-
metic functions. The basic function performed by the device,
ignoring the delay controls,
SUM = (
±AB) + (±CD)
can realize in two steps the familiar summation:
(P+jR)(S+jT)=(PS-RT) + j(PT+SR)
(1)
(2)
by loading the TMC2249A as follows:
where H and L indicate a logic HIGH and LOW.
Thus we can perform a complex multiplication in two clock
cycles. Notice that the user must switch the two components
of the second input vector between the B and D inputs to
obtain the second complex summation.
Calculating a Buttery
Taking advantage of the complex multiply which we imple-
mented above using the TMC2249A, we can expand slightly
to calculate a Radix-2 Buttery, the core of the Fast Fourier
Transform algorithm. To review, the Buttery is calculated
as shown in Figure 6.
Figure 6. Signal Flow of Radix-2 Butterfly
Where
X=A+B(WN
r)
Y=A–B(WN
r),
and WN
r is the complex phase coefcient, or "twiddle factor"
for the N-point transform, which is:
WN
r
=ej(2π/N)
=
cos(2
π/N) + j(sin(2π/N))
=
Re(W) + jIm(W)
with Re and Im indicating the real and imaginary parts of the
vector.
Expanding the complex vectors A and B to calculate X and
Y, we get:
X
=
(Re(A)+jlm(A))+(Re(B)Re(W)-
lm(B)lm(W)+j(Re(B)lm(W)+lm(B)Re(W)))
=
(Re(A)+Re(B)Re(W)-
lm(B)lm(W))+j(lm(A)+Re(B)lm(W)+lm(B)Re(W))
=
Re(X)+jlm(X)
and,
Y
=
(Re(A)+jlm(A))-(Re(B)Re(W)-
lm(B)lm(W)+j(Re(B)lm(W)+lm(B)Re(W)))
=
(Re(A)-
Re(B)Re(W)+lm(B)lm(W))+j(lm(A)-Re(B)lm(W)-
lm(B)Re(W))
=
Re(Y)+jlm(Y)
The buttery is then neatly implemented in four clocks, as
follows:
Notice again that the components of the second vector must
be switched by the user on the second half of the computa-
tion, as well as the parts of the vector presented to the cas-
cade input.
Quadrature Modulation
The TMC2249A can also be used to advantage as a digital-
domain complex frequency synthesizer, as demonstrated in
Figure 7.
Here, orthogonal sinusoidal waveforms are generated digi-
tally in the TMC2330A Coordinate Transformer. These
quadrature phase coefcients are then multiplied with two
input signals, such as digitized analog data.
The TMC2249A then adds these products, which can be out-
put directly to a high-speed digital-to-analog converter such
as the Fairchild TDC1012 for direct waveform synthesis.
This 12-bit, 20MHz DAC is ideally suited to waveform gen-
eration, featuring extremely low glitch energy for low spuri-
ous harmonics and distortion.
TMC2249A Inputs
Resultant
Output
Step
A
B
C
D
NEG1
NEG2
1
P
S
R
T
L
H
(PS-RT)
2
P
T
R
S
L
(PT+SR)
X
A
B
-1
WN
r
Y
Step
TMC2249A Inputs
Result-
ant
Output
AB
C
D
CAS
Input
NEG1
NEG2
1
Re(B)
Re(W) Im(B) Im(W)
Re(A)
L
H
Re(X)
2
Re(B)
Re(W) Im(B) Im(W)
Re(A)
H
L
Re(Y)
3
Re(B)
Im(W) Im(B) Re(W)
Im(A)
L
Im(X)
4
Re(B)
Im(W) Im(B) Re(W)
Im(A)
H
Im(Y)
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相关代理商/技术参数 |
参数描述 |
|---|---|
| TMC2249AH5C1 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| TMC2249AH5C2 | 制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:Digital Mixer 12 x 12 Bit, 60 MHz |
| TMC2249AH6C | 功能描述:视频 IC Digital Mixer RoHS:否 制造商:Fairchild Semiconductor 工作电源电压:5 V 电源电流:80 mA 最大工作温度:+ 85 C 封装 / 箱体:TSSOP-28 封装:Reel |
| TMC2249AH6C1 | 功能描述:视频 IC Digital Mixer RoHS:否 制造商:Fairchild Semiconductor 工作电源电压:5 V 电源电流:80 mA 最大工作温度:+ 85 C 封装 / 箱体:TSSOP-28 封装:Reel |
| TMC2249AH6C2 | 功能描述:视频 IC RoHS:否 制造商:Fairchild Semiconductor 工作电源电压:5 V 电源电流:80 mA 最大工作温度:+ 85 C 封装 / 箱体:TSSOP-28 封装:Reel |
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