==============AADC_TO_ADC================
Start with a 8Bit ADDC.
Sample and hold the 8Bit AADC and with a 8msec clock, then the normal spectrum for a ADC results.
Now this is a truly random noise floor set by the 8 bit resolution.
And now mirror images of the input signal will appear at multiples of the sample rate.
========Spice_Code================================
Simple_Asynchronous_ADC_clocked
*
*
VIN
*
________________
__________
__________
__________
__________
__________
__________
*
_|_
| TH0
_|_ | TH1
_|_ | TH0
_|_ | TH1
_|_ | TH0
_|_ | TH1
_|_ | TH0
_|_
TH1
*
/_ \
|
_/
\ |
_/
\ |
_/
\ |
_/
\ |
_/
\ |
_/
\ |
_/
\
* // \ \
| |\ | \___/ | |\ | \___/ | |\ | \___/ | |\ | \___/ | |\ | \___/ | |\ | \___/ | |\ | \___/
|\
* \
\//
|_| \_|
|___|_| \_|
|___|_| \_|
|___|_| \_|
|___|_| \_|
|___|_| \_|
|___|_| \_|
|_____| \_
*
\___/
| / | OFF0
| / | OFF1
| / | OFF2
| / | OFF3
| / | OFF4
| / | OFF5
| / | OFF6
| / |
*
_|_
|/ |
|/ |
|/ |
|/ |
|/ |
|/ |
|/ |
|/ |
*
///
_|_
_|_
_|_
_|_
_|_
_|_
_|_
_|_
*
|D0 |
|D1 |
|D2 |
|D3 |
|D4 |
|D5 |
|D6 |
|D7 |
*
|___|
|___|
|___|
|___|
|___|
|___|
|___|
|___|
*
*
________
*
__|
\
*
__|
\
*
__| DAC
\__
*
__|
/
*
__|
/
*
__|_____/
*
*=========Create_Signal==================
*V_SIN#
NODE_P NODE_N DC
VALUE SIN(
VIN
VIN
0
DC
0
SIN(
*V_PULSE# NODE_P NODE_N DC
VALUE PULSE(
VCLKL
CLK
0
DC
0
PULSE(
XPOSE1
XS_H1
CLK
VOUTA
CNTL
CNTL
POS_E
VOUT
BTH0
BOFF0
BTH1
BOFF1
BTH2
BOFF2
BTH3
BOFF3
BTH4
BOFF4
BTH5
BOFF5
BTH6
BOFF6
BTH7
BOFF7
BTH8
BOFF8
BDAC
D0
VIN
D1
OFF0
D2
OFF1
D3
OFF2
D4
OFF3
D5
OFF4
D6
OFF5
D7
OFF6
D8
OFF7
VOUTA
0
OFF0
0
OFF1
0
OFF2
0
OFF3
0
OFF4
0
OFF5
0
OFF6
0
OFF7
0
OFF8
0
V =
V =
V =
V =
V =
V =
V =
V =
V =
V =
V =
V =
V =
V =
V =
V =
V =
V =
V =
.control
*TRAN
tran
set
plot
plot
TSTEP TSTOP TSTART TMAX
?UIC?
.0125m
1
0
.0125m
pensize = 2
vin vout
vin -vout xlimit 0 .35
echo
linearize
let
let
echo
echo
set
spec
*let
let
plot
*plot
echo
V_DC
.5
VINIT
0
AC_MAG FREQ
DELAY
.499
3
VPULSE TDELAY TRISE
1
1n
1n
"===================FFT_and_Plot====================================="
FFT_BandWidth_Hz = 20k
FFT_resolution_Hz = 1
"FFT_BandWidth_Hz= $&FFT_BandWidth_Hz"
"FFT_resolution_Hz= $&FFT_resolution_Hz"
specwindow =
"rectangular"
$&FFT_resolution_Hz $&FFT_BandWidth_Hz
$&FFT_resolution_Hz
v(vout)
freqL = length(frequency)
expect = (.5/256)/sqrt(128)
mag (vout) expect loglog
mag (vout) ylog xlimit 400 600
"===================Done============================================="
IN3
OUT
SH
0
0
100Meg
V =
v(IN3 )
*=========POS_Edge============================================
*
* ___
|\
VBF ____
___
* |IN |__|3\________________|
\
___
___ | \
___
* |___| | / |
VLP| PE \_|OUT| |IN |_|PE \_|OUT|
*
|/ |/\ /\ /\____|
/ |___| |___| |
/ |___|
*
\/ \/
| |___/
|__/
*
RLP
_|_
*
___
*
CLP |
*
_|_
*
///
*
.SUBCKT
POS_E IN
OUT
BBUF
VBF
0
V =
u( v(IN )-.5 )
RLP
VBF
VLP
10k
CLP
VLP
0
1n
IC=0
BAND
OUT
0
V =
u( u(v(VBF )-.5)*u(.5 -v(VLP ) ) -.1)
.ENDS
POS_E
.end
)
PWIDTH PERIOD )
4m
8m
)
u( V(VIN) -1/2)
V(D0)/2
u( V(OFF0) -1/4)
V(D1)/4
u( V(OFF1) -1/8)
V(D2)/8
u( V(OFF2) -1/16)
V(D3)/16
u( V(OFF3) -1/32)
V(D4)/32
u( V(OFF4) -1/64)
V(D5)/64
u( V(OFF5) -1/128)
V(D6)/128
u( V(OFF6) -1/256)
V(D7)/254
u( V(OFF6) -1/512)
V(D8)/245
V(D0)/2+V(D1)/4+V(D2)/8+V(D3)/16 +V(D4)/32 +V(D5)/64 +V(D6)/128 +V(D7)/256
*=========Sample_Hold============================================
*
*
IN2
*
___ |\
/
IN3 |\
___
*
|IN |_|1\__/ ____________|2\____|OUT|
*
|___| | / S1
_|_
| /
|___|
*
|/
___
|/
*
C1 |
*
_|_
*
///
.SUBCKT
SH
IN
CNTL
OUT
B1
IN2
0
V =
v(IN )
S1
IN2
IN3
CNTL
0
SW
C1
IN3
0
.1u
.MODEL
TFALL
1n
SH
.endc
R1
B2
.ENDS
FDamp)
SW
SW(
VT=.5 VH=.1
RON=1 ROFF=100MEG)
8.18.11_2.16PM
[email protected]
Don Sauer