An image rejection mixer includes a delay circuit for delaying one of first signals divided by a distribution circuit and a second signal provided to a second mixing circuit by the same delay amount d, or delaying the other one of the first signals divided by the distribution circuit and the second signal provided to a first mixing circuit by the same delay amount d.

A variable frequency oscillator circuit for generating an oscillating signal of a desired frequency, comprising a fixed frequency oscillator; one or more frequency dividers, arranged to receive the output of the fixed frequency oscillator and generate a signal with a divided frequency; and one or mixers, arranged to mix the outputs of the one or more frequency dividers to generate the oscillating signal of the desired frequency. The variable frequency oscillator circuit is arranged to modify the operation of the one or more mixers to suppress any unwanted signals in the generated oscillating signal.

A variable frequency oscillator circuit for generating an oscillating signal of a desired frequency, comprising a fixed frequency oscillator; one or more frequency dividers, arranged to receive the output of the fixed frequency oscillator and generate a signal with a divided frequency; and one or mixers, arranged to mix the outputs of the one or more frequency dividers to generate the oscillating signal of the desired frequency. The variable frequency oscillator circuit is arranged to modify the operation of the one or more mixers to suppress any unwanted signals in the generated oscillating signal.

The disclosure provided a low noise block converter for converting RF signal received from a satellite into IF signal, where the image rejection of the RF signal is performed in two stages through a low noise amplifier (LNA) integrated circuit (IC). The disclosure reduced the number of discrete components by integrating electronic components onto one integrated circuit (or chip), and at the same, improves the noise figure of the LNB converter. The LNB IC comprises LNA circuits, RF path selector, and signal downconverter, where the image rejection is performed by a combination of the LNA circuits and the signal downconverter.

The disclosure provided a low noise block converter for converting RF signal received from a satellite into IF signal, where the image rejection of the RF signal is performed in two stages through a low noise amplifier (LNA) integrated circuit (IC). The disclosure reduced the number of discrete components by integrating electronic components onto one integrated circuit (or chip), and at the same, improves the noise figure of the LNB converter. The LNB IC comprises LNA circuits, RF path selector, and signal downconverter, where the image rejection is performed by a combination of the LNA circuits and the signal downconverter.

According to an embodiment of the inventive concept, an up-down converter includes a first mixer configured to convert an input radio frequency (RF) signal into an intermediate frequency (IF) signal using a first local signal; an IF filter configured to filter the IF signal converted by the first mixer; a second mixer configured to convert the IF signal, which has been filtered by the IF filter, into an output RF signal using a second local signal; and a local oscillator configured to control a frequency of the first local signal and the second local signal based on a frequency of the input RF signal.

According to an embodiment of the inventive concept, an up-down converter includes a first mixer configured to convert an input radio frequency (RF) signal into an intermediate frequency (IF) signal using a first local signal; an IF filter configured to filter the IF signal converted by the first mixer; a second mixer configured to convert the IF signal, which has been filtered by the IF filter, into an output RF signal using a second local signal; and a local oscillator configured to control a frequency of the first local signal and the second local signal based on a frequency of the input RF signal.

A photonic image rejection radio frequency (RF) mixer and a receiver implementing the same may suppress undesired mirror image signals having frequencies at a spectral location that is mirror-symmetric, with respect to a local oscillator (LO), to that of a signal of interest. An upconverted optical beam corresponding to a captured RF beam is extracted by an optical processor. The upconverted optical beam is mixed with the LO to obtain a desired composite optical signal and an undesired composite optical signal, each providing a corresponding beat frequency optical signal at the same frequency. The desired and undesired composite optical signals are captured by multiple optical pickups with relative phase shifts in their beat frequency optical signals which are converted into corresponding electrical signals and combined to suppress the undesired signal.

A photonic image rejection radio frequency (RF) mixer and a receiver implementing the same may suppress undesired mirror image signals having frequencies at a spectral location that is mirror-symmetric, with respect to a local oscillator (LO), to that of a signal of interest. An upconverted optical beam corresponding to a captured RF beam is extracted by an optical processor. The upconverted optical beam is mixed with the LO to obtain a desired composite optical signal and an undesired composite optical signal, each providing a corresponding beat frequency optical signal at the same frequency. The desired and undesired composite optical signals are captured by multiple optical pickups with relative phase shifts in their beat frequency optical signals which are converted into corresponding electrical signals and combined to suppress the undesired signal.

A wide range differential current switching circuit can operate across a wide range of input currents and across a broad range of frequencies. A first differential current source can include a first transistor and a second transistor. The first transistor receives a switching signal and provides an output current and at output node. The second transistor receives an inverted switching signal, the first transistor and the second transistor coupled to each other at a tail node. A current source provides an input current to the tail node. A third transistor can provide a boost current to the tail node while the first transistor is off.