Abstract: A pre-characterised high frequency signal (14) is provided by means of a non-linear circuit, for example an amplifier circuit (10), fed with a first signal (12) with a component at a first, fundamental, frequency (FO). The amplifier circuit generates an output signal comprising harmonic components (14h1, 14h2, 14h3) having stable and predetermined phase relation relative to each other. Information concerning the phase relation of the harmonic frequency components is provided, for example by means of a data file (16). At least two of the harmonic components are at the tenth or lower harmonic frequencies. The signal strength of such low-order harmonic components may be relative high, thus enabling the provision of a pre-characterised high frequency multi-tone signal from the amplifier circuit with high signal to noise ratio.

Abstract: A method of calibrating a high frequency signal measurement system is described. The measurement system is in the form of a network analyzer (6) and has first and second phase-locked signal sources (SS1 & SS2) and at least two measurement receivers (18a, 18b). A phase meter (26) is provided. A reference signal (F0) is outputted at a first frequency from the first signal source (SS1). The second signal source (SS2) steps through a multiplicity of different test frequencies (nF0), being phase-locked with the reference signal (F0), which are applied in turn to a part of the measurement system. Measurements are taken, via the two measurement receivers (18a, 18b), of characteristics of the resulting signal at a measurement plane. The absolute phase of the signal at the measurement plane is also measured with the phase meter (26). Calibration data is generated which relates the characteristics of the signals as measured by the measurement system (6) and the absolute phase as measured with the phase meter (26).

Abstract: A pre-characterised high frequency signal (14) is provided by means of a non-linear circuit, for example an amplifier circuit (10), fed with a first signal (12) with a component at a first, fundamental, frequency (FO). The amplifier circuit generates an output signal comprising harmonic components (14h1, 14h2, 14h3) having stable and predetermined phase relation relative to each other. Information concerning the phase relation of the harmonic frequency components is provided, for example by means of a data file (16). At least two of the harmonic components are at the tenth or lower harmonic frequencies. The signal strength of such low-order harmonic components may be relative high, thus enabling the provision of a pre-characterised high frequency multi-tone signal from the amplifier circuit with high signal to noise ratio.

Abstract: A method of calibrating a high frequency signal measurement system is described. The measurement system is in the form of a network analyser (6) and has first and second phase-locked signal sources (SS1 & SS2) and at least two measurement receivers (18a, 18b). A phase meter (26) is provided. A reference signal (F0) is outputted at a first frequency from the first signal source (SS1). The second signal source (SS2) steps through a multiplicity of different test frequencies (nF0), being phase-locked with the reference signal (F0), which are applied in turn to a part of the measurement system. Measurements are taken, via the two measurement receivers (18a, 18b), of characteristics of the resulting signal at a measurement plane. The absolute phase of the signal at the measurement plane is also measured with the phase meter (26). Calibration data is generated which relates the characteristics of the signals as measured by the measurement system (6) and the absolute phase as measured with the phase meter (26).