Residual Phase Noise Measurements of the Input Section in a Receiver

If not designed properly, the input section of an analog down-converter can introduce phase noise that can prevail over other noise sources in the system. In the paper we present residual phase noise measurements of a simplified input section of a classical receiver that is composed of various commercially available mixers and driven by an LO amplifier. Introduction A classical design approach for receivers operating at microwave frequencies is to downconvert the detected signal to some intermediate frequency before digitizing the signal. The final design of a receiver is chosen depending on performances, which can be described by various parameters. The most important ones are broad-band noise power, close-in noise power, nonlinearity, spurious free dynamic range, temperature stability, isolation between channels (for multiple channels systems), power consumption and price. The main parameter this paper will be investigating is the close-in phase noise of the receiver’s input section. We are interested in measurements of residual phase noise up to 100 kHz away from the 1.3GHz carrier. Figure 1 shows a simplified prototype of the receiver’s input section that has been constructed for applications in high energy physics FERMILAB-CONF-07-536-AD