Frequency converter arrangement

A spectrum analyzer comprising:

• frequency conversion arrangement with at least two successive heterodyne stages, the first heterodyne stage which converts an input signal with an adjustable first heterodyne frequency of a first superposition oscillator, which can be set in fine frequency increments of less than 1 kHz, into a first intermediate frequency, and a second heterodyne stage which converts an input signal with a fixed second heterodyne frequency of a second superposition oscillator into a second intermediate frequency, the difference frequency between the first and second heterodyne frequencies being converted with an adjustable frequency divider into a lower frequency, which is compared in a phase detector to the output frequency of a reference oscillator, and the first superposition oscillator being synchronized with the output frequency of the reference oscillator via a phase control loop with the output signal of this phase detector, characterized in that the reference oscillator is a synthesizer that can be set in fine frequency increments,
• wherein,
• in the first heterodyne stage with a heterodyne frequency that can be set in fine frequency increments, the input signal to be received is converted into a first constant intermediate frequency, which is subsequently converted with a fixed second heterodyne stage into a lower second intermediate frequency.

A modulable high-frequency generator comprising:

• frequency conversion arrangement with at least two successive heterodyne stages, the first heterodyne stage which converts an input signal with an adjustable first heterodyne frequency of a first superposition oscillator, which can be set in fine frequency increments of less than 1 kHz, into a first intermediate frequency, and a second heterodyne stage which converts an input signal with a fixed second heterodyne frequency of a second superposition oscillator into a second intermediate frequency, the difference frequency between the first and second heterodyne frequencies being converted with an adjustable frequency divider into a lower frequency, which is compared in a phase detector to the output frequency of a reference oscillator, and the first superposition oscillator being synchronized with the output frequency of the reference oscillator via a phase control loop with the output signal of this phase detector, characterized in that the reference oscillator is a synthesizer that can be set in fine frequency increments,
• wherein,
• in the first heterodyne stage with a fixed heterodyne frequency, the modulation signal is converted into an intermediate frequency, which is subsequently converted into the desired output frequency in a second heterodyne stage with a heterodyne frequency that can be set in fine increments.