The present invention provides an apparatus for selectively transmitting ions and trapping the ions within a defined 3-dimensional space at atmospheric pressure. The built-in offset can be achieved by varying size, threshold voltage, associated capacity or associated resistance of the transistors within the sense amplifier. A heated or chilled fluid is conducted through a supply lumen of the catheter and into the bladder. Accordingly, even though an image written in a paper of a paper size not treatable on the receiving side is transmitted from the transmitting side to the receiving side, because the image is downsized, the image can be reproduced on the receiving side. Estimating the phase offset over multiple symbols in the received RF signal can lower the error rate.