Damien B. wrote: > Matt in a previous thread you were talking about making d/b that let > DC component pass: > > >>If there is enough interest, I might make such a set of boards. If someone >>else >>is interested in the design, the BasicRX/TX are a great starting point, and I >>can offer guidance.
I have seen very little interest in that. > When i'm inspecting the my FIR output, it's really difficult to > measure a 30ns (one sample) delay if the signal is not clean. This is unrelated to the DC component issue. > Would it > be possible to make a quick but not perfect hack of the basicTX and > RX, something like: > - removing transformer > - Short-cut pin 3 to 6 and 1 to 4 > the resulting impedance would be 40 Ohms (50 // 50+200+50), but is it > really bad for low freq square wave < 2MHz ? Sort of. You would remove the transformer first. Then you have 2 options -- 1> Feed your signal to the + input, and send the reference voltage (Vdd/2, 1.65V, available on the board) to the - input. The problem here is that the ADC expects the signals to be +/- 1V from the reference, 1.65V. Your signal will need to be properly biased. The better option is: 2> Put an AD8132 or similar differential amplifier in the circuit. You can find the appropriate connections in the AD8132 datasheet. This is what I would do if I did make a DC version of the BasicRX Matt _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
