For SSB operation the 36 MHz signal is mixed down to 6 MHz. This 6 MHz signal is again feet into a phase comparator where it is compared to the signal of the 6 MHz VFO. This way the stable 6 MHz VFO is able to control the 36 MHz VFO which again is able to control the 96 MHz VFO. A well designed 6 MHz VFO is by far good enough for SSB, so the 96 MHz VFO in this system is good enough too. (For experts: since the time constant of the PLL loop filter is quite large, the phase noise of the 96 MHz VFO is significantly reduced also.) The frequency range of the 6 MHz oscillator is only 500 kHz, but this is completely sufficient since all SSB/CW operation is located in the 144 – MHz area.
The use of UHF to provide programming that otherwise would not be available, such as province-wide educational services (BC's Knowledge: channel, or TVOntario - the first UHF originating station in Canada), Télé-Québec , French language programming outside Québec and ethnic/multilingual television services), has therefore become common. Third networks such as Quatre-Saisons or Global often will rely heavily on UHF stations as repeaters or as a local presence in large cities where VHF spectrum is largely already full. The original digital terrestrial television stations were all UHF broadcasts, although some digital broadcasts returned to VHF channels after the digital transition was completed in August 2011. 
The analytic determination of the MPI of a mixer circuit can also be performed using a method based on the Volterra series and the method of nonlinearly controlled sources without the need for an input-output description. This method enables the calculation of the spectral components of the state variables at an arbitrary node of networks with nonlinear time-invariant elements with small-signal excitations. This method is extended in this thesis to networks with a large-signal excitation as to be appropriate for the analysis of mixer circuits with switching behaviour. The extended method is then applied for the nonlinearity analysis of a mixer circuit and the calculation of the MPI. The noise behaviour of the mixer is explained in this work by means of an example MOS mixer circuit. Here, the contribution of each circuit element to the output noise is determined and a closed-form expression of the noise figure in dependency on the design parameters is derived. In the last part of the thesis a systematic design flow for mixers based on the MPI is proposed. Based on given design specifications and candidate mixer architectures, the proposed design flow enables the designer through the comparison of different architecture/technology-combinations to design a mixer circuit, which mostly fulfills the design specifications for a certain application.