> > If there is no dc-removing capacitor in the circuitry , then should I > not expect that for a board using a single (positive) supply, that the > signal is always above zero? >
No, you can put a negative voltage in, as long as it doesn't go below -3.33V. You need to look at the schematics -- the 8132 is a differential opamp with a common mode output set at 3.3V/2. Basically, the differential amps will clip if you go outside the range of -3.3V to +3.3V. You will also damage the differential amp if you go below -3.3V. The ADC will clip if you go outside the range -2V to +2V when set for minimum gain. Back to the subject of what your signal generator is doing, I don't know. If you measure the voltage on the sma connector with nothing connected, you will see that it is 0. If you connect a 1 V source through a 50 ohm resistor, you will see that there is 0.5V at the connector. If you connect -1 V through a 50 ohm resistor, you will see -0.5V at the connector. Matt _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
