Rita » History » Version 7
laforge, 02/19/2016 10:48 PM
add more notes on the scope images
1 | 4 | laforge | [[PageOutline]] |
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2 | |||
3 | = TRF6151C = |
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4 | 6 | laforge | This is the Texas Instruments RF Chip TRF6151C (Rita) |
5 | 1 | laforge | |
6 | It includes a VCO, Mixers, etc. |
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7 | 6 | laforge | |
8 | Data sheet is available from http://www.52rd.com/bbs/Detail_RD.BBS_8719_68_1_1.html but registration to the chinese forum |
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9 | is required for download. |
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10 | 2 | laforge | |
11 | == TSP == |
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12 | |||
13 | The TSP to the TRF6151 uses three wires: |
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14 | * CLOCK (regular CLK_13M) |
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15 | * STROBE (generated by TPU) |
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16 | * DATA (provided by TPU at falling edge of CLOCK, TRF samples data at rising edge of CLOCK) |
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17 | |||
18 | 3 | laforge | [[Image(Rita:trf6151_tsp.png)]] |
19 | 4 | laforge | |
20 | == Analog I/Q baseband output == |
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21 | |||
22 | 7 | laforge | During development I've taken some measurements of the I/Q output of the TRF6151. This signal |
23 | is fed to the [wiki:TWL3025] baseband ADC inputs. |
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24 | 1 | laforge | |
25 | 4 | laforge | The green and black graph of the diagrams below are the "I" channel positive and negative signal. |
26 | 7 | laforge | The magenta graph (M1) is the difference signal computed by the Scope. |
27 | 1 | laforge | |
28 | 7 | laforge | All voltages have to be multiplied by a factor of 10, as 10:1 probes were used. |
29 | |||
30 | 4 | laforge | === baseband output in idle mode listening on paging channel === |
31 | |||
32 | 7 | laforge | This is zoomed out to a very long timebase to see the Rx activity at 1.8 second intervals, |
33 | 4 | laforge | which apparently was the paging channel for the paging group of that IMSI. |
34 | |||
35 | [[Image(Rita:trf6151_iq_rx_paging_channel.png)]] |
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36 | |||
37 | === multiple consecutive bursts === |
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38 | |||
39 | This shows multiple consecutive received bursts. |
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40 | You can see that there is a DC offset when the TRF6151 is powered up, but you can't really see data on that DC offset |
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41 | |||
42 | [[Image(Rita:trf6151_iq_rx_burst_distance.png)]] |
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43 | |||
44 | === a single burst === |
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45 | |||
46 | [[Image(Rita:trf6151_rx_iq_one_burst.png)]] |
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47 | |||
48 | === bits of a burst === |
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49 | |||
50 | [[Image(Rita:trf6151_rx_iq_bits_of_burst.png)]] |