Abstract: To minimize the overall circuitry necessary in a multiband-frequency generator, output terminals of a voltage-controlled multiband oscillator (22-1, . . . , 22-N) are coupled to a frequency synthesis unit (10) via a frequency selective coupling unit (24). The frequency synthesis unit (10) derives a phase difference between a frequency control input signal and the output signal of the frequency selective coupling unit (24) to control the voltage-controlled multiband oscillator (22-1, . . . , 22-N).

Abstract: A dual channel receiver (100) includes a front end bandpass filter (120) that has a front end bandwidth, a first mixer (130), a second mixer (135), and two essentially identical receiver back ends (190, 195). The front end bandpass filter splits a received signal into a first signal (121) and a second signal (122) of essentially equal signal strengths and provides out of band isolation between first and second signal outputs (123, 124). The first mixer is coupled to the first signal and to a high side injection signal (131), and generates a first mixer output signal (132). The second mixer is coupled to the second signal and to a low side injection signal (136), and generates a second mixer output signal (137). Each of the two essentially identical receiver back ends is coupled to one of the first and second mixer output signals.

Abstract: In a receiver the input signal is converted by a mixer into two quadrature IF signals. The quadrature IF signals are amplified by an amplifier and filtered by a filter. A polyphase filter suppresses signals having frequencies above a predetermined frequency. A second mixer converts the filtered IF signal into a second IF signal. This second IF signal is filtered by a second polyphase filter which suppresses signals having a frequency below a predetermined frequency. In this way a band-pass transfer function is obtained having a first edge defined by the first polyphase filter and having the second defined by the second polyphase filter. In an embodiment of the invention, the cut off frequencies of the polyphase filters are equal to zero, resulting in a transfer function for the complete receiver having cut off frequencies independent from the component values use in the polyphase filters.