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. 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). ![]() 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.
0 Comments
Leave a Reply. |