Wide dynamic range product detector

Claim 1

A signal translating system for providing an information signal having at least one desired frequency at a system output terminal, said system comprising: a signal combining means including first, second, third and fourth switching transistors arranged in a quad configuration, said signal combining means having first and second input terminals and first and second output terminals, each of said switching transistors having a switching control input means; first means for connecting the control input means of said first and third switching transistors at a first junction terminal; second means for connecting the control input means of said second and fourth switching transistors at a second junction terminal; means for applying an input signal having at least one frequency tone in push-pull between said first and second signal combining means input terminals; means for supplying a switching signal in push-pull between said first and second junction terminals; said signal combining means providing at said first output terminal, in response to said input signal and to said switching signal, a first signal having a first and second component, said first component corresponding to the product of said switching signal and said input signal at a certAin phase, said first signal second component corresponding to intermodulation products of said signals, said signal combining means further providing a second signal having first and second components at said second output terminal, said second signal first component corresponding to the product of said switching signal and said input signal with a phase difference of 180 with respect to said certain phase, said second signal second component corresponding to said intermodulation products; first frequency selective means including a first dummy load coupled to said signal combining means first output terminal for passing signals in a desired frequency range to an output terminal thereof and for absorbing signals in an undesired frequency range in said first dummy load; second frequency selective means including a second dummy load coupled to said switching means second output terminal for passing signals in said desired frequency range to an output terminal thereof and for absorbing signals in said undesired frequency range in said second dummy load; first amplifying means coupled to said first frequency selective means output terminal, for providing at an output terminal thereof a first amplified signal; second amplifying means coupled to said second frequency selective means output terminal, for providing at an output terminal thereof a second amplified signal; and a difference circuit coupled to the output terminals of said first and second amplifying means, for providing said information signal at said system output terminal, said information signal corresponding to the difference between said first signal first component and said second signal first component, said intermodulation products being substantially reduced at said system output terminal.

Claim 7

A system for translating an intermediate frequency signal to a video frequency signal and for providing said video signal at a system output terminal, said intermediate frequency signal having at least one frequency tone, said system substantially reducing intermodulation products, said system comprising: a mixer having first, second, third and fourth field effect transistors arranged in a quad configuration, said mixer having first and second input terminals and first and second output terminals, each of said field effect transistors having a control electrode; first means for connecting the control electrodes of said first and third field effect transistors at a first junction terminal; second means for connecting the control electrodes of said second and fourth field effect transistors at a second junction terminal; means for applying said intermediate frequency signal in push-pull between said first and second mixer input terminals; means for applying a switching signal in push-pull between said first and second junction terminals; said mixer, providing at said first output terminal in response to said intermediate freQuency signal and to said switching signal, a first signal having a first and a second component, said first signal first component corresponding to the product of said switching signal and said intermediate frequency signal, said first signal first component having a certain phase, said first signal second component corresponding to said intermodulation products, said mixer further providing at said second output terminal, a second signal having a first and second component, said second signal first component corresponding to the product of said switching signal and said intermediate frequency signal, said second signal first component being 180* out of phase with respect to said first signal first component, said second signal second component corresponding to said intermodulation products; a first and second filter, each coupled to the first output terminal of said mixer, for passing signals in a desired frequency range through the first filter to an output terminal thereof and for absorbing signals in an undesired frequency range through the second filter, said second filter being terminated in a dummy load; a third and fourth filter, each coupled to the second output terminal of said mixer, for passing signals in said desired frequency range through the third filter to an output terminal thereof and for absorbing signals in said undesired frequency range through the fourth filter, said fourth filter being terminated in another dummy load; a first amplifier, coupled to said first filter for providing at an output terminal thereof a first amplified signal corresponding to the signal appearing at the output terminal of said first filter; a second amplifier, coupled to said third filter, for providing at an output terminal thereof a second amplified signal corresponding to the signal appearing at the output terminal of said third filter; and a differential amplifier, responsive to said first and second amplified signals, for providing at said system output terminal said video signal, said video signal corresponding to the difference between said first signal first component and said second signal first component, said intermodulation products being substantially reduced at said system output terminal.

Claim 8

A system for translating an intermediate frequency signal to a video frequency signal and for providing said video signal at a system output terminal, said intermediate frequency signal having at least one frequency tone, said system substantially reducing intermodulation products, said system comprising: a mixer having first, second, third and fourth field effect transistors arranged in a quad configuration, said mixer having first and second input terminals and first and second output terminals, each of said field effect transistors having a control electrode; first means for connecting the control electrodes of said first and third field effect transistors at a first junction terminal; second means for connecting the control electrodes of said second and fourth field effect transistors at a second junction terminal; means for applying said intermediate frequency signal in push-pull between said first and second mixer input terminals; means for applying a switching signal in push-pull between said first and second junction terminals; said mixer, providing at said first output terminal in response to said intermediate freQuency signal and to said switching signal, a first signal having a first and a second component, said first signal first component corresponding to the product of said switching signal and said intermediate frequency signal, said first signal first component having a certain phase, said first signal second component corresponding to said intermodulation products, said mixer further providing at said second output terminal, a second signal having a first and second component, said second signal first component corresponding to the product of said switching signal and said intermediate frequency signal, said second signal first component being 180* out of phase with respect to said first signal first component, said second signal second component corresponding to said intermodulation products; a first and second filter, each coupled to the first output terminal of said mixer, for passing signals in a desired frequency range through the first filter to an output terminal thereof and for absorbing signals in an undesired frequency range through the second filter, said second filter being terminated in a dummy load; a third and fourth filter, each coupled to the second output terminal of said mixer, for passing signals in said desired frequency range through the third filter to an output terminal thereof and for absorbing signals in said undesired frequency range through the fourth filter, said fourth filter being terminated in another dummy load; a first amplifier, coupled to said first filter for providing at an output terminal thereof a first amplified signal corresponding to the signal appearing at the output terminal of said first filter; a second amplifier, coupled to said third filter, for providing at an output terminal thereof a second amplified signal corresponding to the signal appearing at the output terminal of said third filter; and a differential amplifier, responsive to said first and second amplified signals, for providing at said system output terminal said video signal, said video signal corresponding to the difference between said first signal first component and said second signal first component, said intermodulation products being substantially reduced at said system output terminal.