comparison: content/hp8662a_3.rst
content/hp8662a_3.rst
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| 24 procedure to follow in on the Service Sheet H. The general block diagram of | 24 procedure to follow in on the Service Sheet H. The general block diagram of |
| 25 this section is as follow: | 25 this section is as follow: |
| 26 | 26 |
| 27 .. image:: {static}/images/hp8662a/LF_block_diagram.png | 27 .. image:: {static}/images/hp8662a/LF_block_diagram.png |
| 28 :class: image-process-large-photo | 28 :class: image-process-large-photo |
| 29 :alt: LF block diagram | |
| 29 | 30 |
| 30 This Low Frequency Section consists in no less than 4 phase locked loops in | 31 This Low Frequency Section consists in no less than 4 phase locked loops in |
| 31 order to achieve adjustable frequency synthesis with the expected stability and | 32 order to achieve adjustable frequency synthesis with the expected stability and |
| 32 resolution. | 33 resolution. |
| 33 | 34 |
| 55 | 56 |
| 56 Here is a more detailed vue of the block diagram of the low frequency section: | 57 Here is a more detailed vue of the block diagram of the low frequency section: |
| 57 | 58 |
| 58 .. image:: {static}/images/hp8662a/sheet_H.png | 59 .. image:: {static}/images/hp8662a/sheet_H.png |
| 59 :class: image-process-large-photo | 60 :class: image-process-large-photo |
| 61 :alt: LF detailed block diagram | |
| 60 | 62 |
| 61 | 63 |
| 62 Fixing the Error 04 | 64 Fixing the Error 04 |
| 63 =================== | 65 =================== |
| 64 | 66 |
| 132 | 134 |
| 133 For example, at 100.3MHz, we have a decent signal: | 135 For example, at 100.3MHz, we have a decent signal: |
| 134 | 136 |
| 135 .. image:: {static}/images/hp8662a/working_not_quite_3.jpg | 137 .. image:: {static}/images/hp8662a/working_not_quite_3.jpg |
| 136 :class: image-process-large-photo | 138 :class: image-process-large-photo |
| 139 :alt: generate a 100.3MHz signal | |
| 137 | 140 |
| 138 .. image:: {static}/images/hp8662a/working_not_quite_3_sa.jpg | 141 .. image:: {static}/images/hp8662a/working_not_quite_3_sa.jpg |
| 139 :class: image-process-large-photo | 142 :class: image-process-large-photo |
| 143 :alt: 100.3MHz signal - spectrum | |
| 140 | 144 |
| 141 but at 101.0Mhz, it begins to looks pretty messy: | 145 but at 101.0Mhz, it begins to looks pretty messy: |
| 142 | 146 |
| 143 .. image:: {static}/images/hp8662a/working_not_quite_2.jpg | 147 .. image:: {static}/images/hp8662a/working_not_quite_2.jpg |
| 144 :class: image-process-large-photo | 148 :class: image-process-large-photo |
| 149 :alt: generate a 101.0MHz signal | |
| 145 | 150 |
| 146 .. image:: {static}/images/hp8662a/working_not_quite_2_sa.jpg | 151 .. image:: {static}/images/hp8662a/working_not_quite_2_sa.jpg |
| 147 :class: image-process-large-photo | 152 :class: image-process-large-photo |
| 153 :alt: 101.0MHz signal - noisy spectrum | |
| 148 | 154 |
| 149 and 101.9Mhz shows "nice" side bands: | 155 and 101.9Mhz shows "nice" side bands: |
| 150 | 156 |
| 151 .. image:: {static}/images/hp8662a/working_not_quite.jpg | 157 .. image:: {static}/images/hp8662a/working_not_quite.jpg |
| 152 :class: image-process-large-photo | 158 :class: image-process-large-photo |
| 159 :alt: generate a 101.9MHz signal | |
| 153 | 160 |
| 154 .. image:: {static}/images/hp8662a/working_not_quite_sa.jpg | 161 .. image:: {static}/images/hp8662a/working_not_quite_sa.jpg |
| 155 :class: image-process-large-photo | 162 :class: image-process-large-photo |
| 163 :alt: 101.9MHz signal - with spurious side bands | |
| 156 | 164 |
| 157 The problem seems quite clear: some PLL cannot lock at specific frequencies, | 165 The problem seems quite clear: some PLL cannot lock at specific frequencies, |
| 158 but the strange thing is that this unlock PLL does not produces an error. | 166 but the strange thing is that this unlock PLL does not produces an error. |
| 159 | 167 |
| 160 So I tried to figure out which boad assembly could be the culprit. With no | 168 So I tried to figure out which boad assembly could be the culprit. With no |
| 178 | 186 |
| 179 For example, a 101MHz signal which was very unstable before now looks like: | 187 For example, a 101MHz signal which was very unstable before now looks like: |
| 180 | 188 |
| 181 .. image:: {static}/images/hp8662a/working_101.jpg | 189 .. image:: {static}/images/hp8662a/working_101.jpg |
| 182 :class: image-process-large-photo | 190 :class: image-process-large-photo |
| 191 :alt: 101.0MHz signal - better spectrum |
