Digital Signal Processing Reference
In-Depth Information
20
15
10
5
0
2
4
6
8
10
12
14
16
18
(a) Sample
5
4
3
2
1
0
0
2
4
6
8
10
12
14
16
18
(b) Sample
Figure 3.15:
(a) Analog signal (dashed), analog sample values (circles), and quantized samples (stairstep).
Due to clipping, the sample values for sample times 2-6 are limited to quantized level 15; (b) Error signal,
difference between original signal and the quantized signal at sample times.
=
BinOut
LV xBinaryCodeMethods(BitsQ,SR,Bias,Freq,Amp,CM,PlotType)
(see exercises below) affords the opportunity to experiment with the analog-to-digital conversion of a
test sine wave, using either of the two formats mentioned above. It allows you to select the number of
quantization bits
BitsQ
, the sample rate
SR
, amount of bias to the input signal
Bias
, test sine wave
frequency
Freq
, test sine wave amplitude
Amp
, coding method
CM
, which includes
Sign plus Magnitude
and
Offset
, and
PlotType
, which displays the quantized output in volts or as multiples of the LSB.
Example 3.17.
Demonstrate the Sign Plus Magnitude conversion method (or format) using the script
LVxBinaryCodeMethods
.
Figure 3.17, plots (a) and (b), show a portion of the result from using parameters of
SR
= 1000
Hz,
Freq
=10Hz,
Amp
= 170,
BitsQ
= 2 Bits,
Bias
= None, and
CM
=
Sign plus Mag,
and
PlotType
as
volts. The call is
