Patent ID: 6137440
Filing Date: 2000-10-24
Classification: G01K,H03B

Abstract:
An active noise source for calibrating a radiometer, said noise source comprising:a noise equivalent circuit having a gate port, drain port and source port;a source inductance providing series feedback coupled to the source port of the noise equivalent circuit;an output impedance matching network terminated at the drain port of the noise equivalent circuit, said output impedance matching network including a load;an input impedance matching network connected to the gate port of the noise equivalent circuit, said input impedance matching network including an input port, said input port reflecting a hot thermal radiation temperature and a cold thermal radiation temperature to calibrate the radiometer; anda bias circuit applying DC bias to the output impedance matching network and the input impedance matching network to generate the hot thermal radiation temperature and the cold thermal radiation temperature alternately at the gate port of the noise equivalent circuit.