a signal transmission gate is disclosed for gating signals including those at af and rf frequencies in response to a gating signal . for the duration of the gating signal , the transmission gate has a low signal pass resistance . in the absence of a gating signal , the transmission gate has a high signal pass resistance . the transmission gate is bidirectional in that it can pass or block signals in two directions . the transmission gate is especially well - adapted for use in applications requiring a high signal shunt resistance when the transmission gate is on which is achieved by gating with a high impedance source . an embodiment of one such high impedance source is also disclosed .