Patent ID: 7948326

Claim:
Method for implementing a frequency change while retaining a phase relationship between a plurality of devices wherein each device comprises at least one signal generator for exciting a device under test and at least one local oscillator connected to at least one mixer for receiving a test signal obtained from the device under test according to the superposition principle, comprising in the event of said frequency change, (a) initially varying only a frequency of the local oscillator of each of said devices, and maintaining a frequency of the signal generator of each of said devices, and (b) then varying only a frequency of at least one signal generator, and maintaining a frequency of the local oscillator of each of said devices, or, in the event of said frequency change, (a) initially varying only a frequency of at least one signal generator, and maintaining a frequency of the local oscillator of each of said devices, and (b) then varying only a frequency of the local oscillator of each of said devices, and maintaining the frequency of the signal generator of each of said devices.