Search This Blog

Tuesday, September 25, 2007

ASCII Chart

ASCII Chart


Decimal Octal Hex Character
0 0 00 NUL
1 1 01 SOH
2 2 02 STX
3 3 03 ETX
4 4 04 EOT
5 5 05 ENQ
6 6 06 ACK
7 7 07 BEL
8 10 08 BS
9 11 09 HT
10 12 0A LF
11 13 0B VT
12 14 0C FF
13 15 0D CR
14 16 0E SO
15 17 0F SI
16 20 10 DLE
17 21 11 DC1
18 22 12 DC2
19 23 13 DC3
20 24 14 DC4
21 25 15 NAK
22 26 16 SYM
23 27 17 ETB
24 30 18 CAN
25 31 19 EM
26 32 1A SUB
27 33 1B ESC
28 34 1C FS
29 35 1D GS
30 36 1E RS
31 37 1F US
32 40 20 SP
33 41 21 !
34 42 22 "
35 43 23 #
36 44 24 $
37 45 25 %
38 46 26 &
39 47 27 '
40 50 28 (
41 51 29 )
42 52 2A *
43 53 2B +
44 54 2C ,
45 55 2D -
46 56 2E .
47 57 2F /
48 60 30 0
49 61 31 1
50 62 32 2
51 63 33 3
52 64 34 4
53 65 35 5
54 66 36 6
55 67 37 7
56 70 38 8
57 71 39 9
58 72 3A :
59 73 3B ;
60 74 3C <
61 75 3D =
62 76 3E >
63 77 3F ?
Decimal Octal Hex Character
64 100 40 @
65 101 41 A
66 102 42 B
67 103 43 C
68 104 44 D
69 105 45 E
70 106 46 F
71 107 47 G
72 110 48 H
73 111 49 I
74 112 4A J
75 113 4B K
76 114 4C L
77 115 4D M
78 116 4E N
79 117 4F O
80 120 50 P
81 121 51 Q
82 122 52 R
83 123 53 S
84 124 54 T
85 125 55 U
86 126 56 V
87 127 57 W
88 130 58 X
89 131 59 Y
90 132 5A Z
91 133 5B [
92 134 5C \
93 135 5D ]
94 136 5E ^
95 137 5F _
96 140 60 `
97 141 61 a
98 142 62 b
99 143 63 c
100 144 64 d
101 145 65 e
102 146 66 f
103 147 67 g
104 150 68 h
105 151 69 i
106 152 6A j
107 153 6B k
108 154 6C l
109 155 6D m
110 156 6E n
111 157 6F o
112 160 70 p
113 161 71 q
114 162 72 r
115 163 73 s
116 164 74 t
117 165 75 u
118 166 76 v
119 167 77 w
120 170 78 x
121 171 79 y
122 172 7A z
123 173 7B {
124 174 7C |
125 175 7D }
126 176 7E ~
127 177 7F DEL
Ref : http://www.acm.uiuc.edu/webmonkeys/book/c_guide/a.html

ATTEMPT TO DEFINE AN ALREADY DEFINED SYMBOL

Problem :

C:\KEIL\C51\ASM\C8051F120.INC(17): error A10: ATTEMPT TO DEFINE AN ALREADY DEFINED SYMBOL

Resolution :

The problem here is by default keil defines 8051 registers.

Solution

$NOMOD51 ;ask keil not to define 8051 registers
$INCLUDE (REG320.DEF) ; include your processor definition file.

Wednesday, September 12, 2007

Digital Filter Design

The digital filters are basically designed from analog filters.

The procedure :

  1. Take the Frequency and magnitude specifications of equivalent filter.
  2. Design analog filter for given specification( H(s) )
  3. Apply the suitable transformation ( H(s) < - > H(z) )
  4. Realize the digital filter from the system function H(z).
Ref : DSP , J.S. Chitode

Saturday, September 8, 2007

Understand dB

For example,

gain response could be specified as 0.707 or as −3.0103 dB,

gain might be specified as 0.0001 or −80.0 dB.

Formula --

gain dB = 20⋅ log(gain)

Reason :

values in decibels are more manageable for very small
gains



reference :

1: Practical Analog and Digital Filter Design (Artech House Microwave Library)
by Les Thede