| 78 | ===== Spectrum Analyzer ===== |
| 79 | Hardware Spectrum Analyzer - Tektronix SA2600: |
| 80 | * Wire measurement must be connect with 30dB attenuator in order to avoid saturation |
| 81 | * Wireless measurement requires much higher gain than using wire |
| 82 | {{{#!html |
| 83 | <table align=center cellpadding=10 width=50%> |
| 84 | <tr> |
| 85 | <td><center><img src="http://www.orbit-lab.org/raw-attachment/wiki/Other/Summer/2015/aSDR3/Tektronix.png" height=300><center></td> |
| 86 | </tr> |
| 87 | <tr> |
| 88 | <td><center><b>Figure 2. Tektronix SA2600<b><center></td> |
| 89 | </tr> |
| 90 | </table> |
| 91 | }}} |
| 92 | |
| 93 | Software Spectrum Analyzer - RTLSDR Scanner: |
| 94 | * PROS: user-friendly, convenient, remote access, software-based spectrum analyzer |
| 95 | * CONS: Realtek 2832 EZCap can’t tune to frequencies higher than 1.8GHz |
| 96 | |
| 97 | {{{#!html |
| 98 | <table align=center cellpadding=10 width=50%> |
| 99 | <tr> |
| 100 | <td><center><img src="http://www.orbit-lab.org/raw-attachment/wiki/Other/Summer/2015/aSDR3/RTLSDR.png" height=250><center></td> |
| 101 | </tr> |
| 102 | <tr> |
| 103 | <td><center><b>Figure 3. RTLSDR Scanner<b><center></td> |
| 104 | </tr> |
| 105 | </table> |
| 106 | }}} |
| 107 | |
79 | | |
80 | | ===== Spectrum Analyzer ===== |
81 | | * Hardware Spectrum Analyzer - Tektronix SA2600 |
82 | | |
83 | | {{{#!html |
84 | | <table align=center cellpadding=10 width=50%> |
85 | | <tr> |
86 | | <td><center><img src="http://www.orbit-lab.org/raw-attachment/wiki/Other/Summer/2015/aSDR3/Tektronix.png" height=300><center></td> |
87 | | </tr> |
88 | | <tr> |
89 | | <td><center><b>Figure 2. Tektronix SA2600<b><center></td> |
90 | | </tr> |
91 | | </table> |
92 | | }}} |
93 | | |
94 | | * Software Spectrum Analyzer - RTLSDR Scanner |
95 | | * PROS: user-friendly, convenient, remote access, software-based spectrum analyzer |
96 | | * CONS: Realtek 2832 EZCap can’t tune to frequencies higher than 1.8GHz |
97 | | |
98 | | {{{#!html |
99 | | <table align=center cellpadding=10 width=50%> |
100 | | <tr> |
101 | | <td><center><img src="http://www.orbit-lab.org/raw-attachment/wiki/Other/Summer/2015/aSDR3/RTLSDR.png" height=250><center></td> |
102 | | </tr> |
103 | | <tr> |
104 | | <td><center><b>Figure 3. RTLSDR Scanner<b><center></td> |
105 | | </tr> |
106 | | </table> |
107 | | }}} |
108 | | |
| 109 | GNU Radio is an important tool to obtain the Waterfall Plot. |
| 110 | [http://www.orbit-lab.org/attachment/wiki/Other/Summer/2015/aSDR3/Necessary_Commands_Links_GNU.docx.pdf How to use GNU Radio] |
116 | | noise = variance = mean ( signal - mean ( signal ) ) |
117 | | |
118 | | noise [dB] = 10 log (noise power) |
119 | | |
120 | | signal [dB] = 10 log (signal power) |
121 | | |
122 | | SNR = signal power / noise power |
123 | | |
124 | | SNR [dB] = signal [dB] - noise [dB] |
| 116 | The relationship between signal, noise, SNR: |
| 117 | * noise = variance = mean ( signal - mean ( signal ) ) |
| 118 | * noise [dB] = 10 log (noise power) |
| 119 | * signal [dB] = 10 log (signal power) |
| 120 | * SNR = signal power / noise power |
| 121 | * SNR [dB] = signal [dB] - noise [dB] |
| 122 | |
| 123 | MATLAB code to measure SNR: |