![]() ![]() This output would suffice for the line input of the sound card, but without the AGC working an extra powering is needed. The second step, the down-conversion to a 12 KHz IF, has been solved using the 467 KHz mixer used in the other receivers modifications presented in this site. These two points are red marked in the following figure: This effect can be solved just by tuning a couple of resonators while monitoring it in a spectrum analyzer. This does not have a visible effect in the base band AM signal (aside from a Signal to Noise Ratio reduction), but it has for the 12 KHz DRM output. The last fact relating to this filter is that it may have not been correctly tuned in the manufacturing process, causing an asymmetric response. A simple filter design will be presented soon, for the moment an unfiltered signal is still suitable. Grundig YACHT BOY 208 Operation & user’s manual (7 pages) Pages: 7 Size: 2.39 Mb. The effects of this greater bandwidth are a noise increment and the appearance of the image frequency (current transmissions are isolated enough to avoid this last one). Database contains 1 Grundig YACHT BOY 208 Manuals (available for free online viewing or downloading in PDF): Operation & user’s manual. This can be solved just by adjusting a resonator blue marked in figure 2.Īnother important fact about this signal bandwidth is that it is only limited by the RF and IF1 (55.85 MHz) filters, which is quite wide (a 50 KHz BW was measured). ![]() We have found it to be as big as 300 Hz in one model. This frequency is set to be 455 KHz although it could be shipped with a centering error. We are working it out by now but, for the moment, an audio amplifier at the output does the work. It must be taken into account that the signal level at this point is not affected by the AGC (Automatic Gain Control), so it will not be very powerful. ![]()
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