A system for hybrid modulation and demodulation includes a transmitter and a receiver. The transmitter is configured to receive a hybrid signal of a space-ground link system (SGLS), including a first component and a second component; perform a double sideband (DSB) modulation on the first component using a carrier frequency to obtain a first waveform; perform a single sideband (SSB) modulation on the second component using the carrier frequency to obtain a second waveform; mix the first waveform and the second waveform to generate a hybrid waveform; and transmit the hybrid waveform. The receiver is configured to receive the hybrid waveform; determine the carrier frequency; separate the first waveform and the second waveform; perform a DSB demodulation on the first waveform to obtain a first demodulated signal; and perform an SSB demodulation on the second waveform to obtain a second demodulated signal.

A system for hybrid modulation and demodulation includes a transmitter and a receiver. The transmitter is configured to receive a hybrid signal of a space-ground link system (SGLS), including a first component and a second component; perform a double sideband (DSB) modulation on the first component using a carrier frequency to obtain a first waveform; perform a single sideband (SSB) modulation on the second component using the carrier frequency to obtain a second waveform; mix the first waveform and the second waveform to generate a hybrid waveform; and transmit the hybrid waveform. The receiver is configured to receive the hybrid waveform; determine the carrier frequency; separate the first waveform and the second waveform; perform a DSB demodulation on the first waveform to obtain a first demodulated signal; and perform an SSB demodulation on the second waveform to obtain a second demodulated signal.

A mixer for mixing a radio frequency signal is described. The mixer includes a local oscillator input, a phase adjustment module, and at least one mixing channel. The local oscillator input is configured to receive a local oscillator signal. The phase adjustment module is configured to control a phase of the local oscillator signal in order to add a desired amount of delay to the local oscillator signal, thereby generating at least one adapted oscillator signal. The at least one adapted oscillator signal has a desired phase difference compared to the local oscillator signal. The at least one mixing channel includes at least one mixer unit having at least one signal input. The at least one mixing channel is configured to receive the at least one adapted oscillator signal. The at least one mixing channel further is configured to forward the adapted oscillator signal to the mixer unit. The at least one signal input is configured to receive an input signal. The at least one signal input further is configured to forward the input signal to the mixer unit. The mixer unit is configured to mix the at least one adapted oscillator signal with the input signal, thereby generating a mixer output signal.

In a receiver that demodulates a received signal, deterioration of signal quality is suppressed. A current output unit generates and outputs, from a voltage signal, a current signal including a predetermined offset current in a low-frequency component between a high-frequency component having a frequency higher than a predetermined frequency and the low-frequency component having a frequency lower than the predetermined frequency. A demodulation unit demodulates the high-frequency component. A filter circuit passes, in the current signal, the high-frequency component from a current output unit to the demodulation unit, and causes the low-frequency component to flow from the current output unit to a predetermined reference potential point.

In a receiver that demodulates a received signal, deterioration of signal quality is suppressed. A current output unit generates and outputs, from a voltage signal, a current signal including a predetermined offset current in a low-frequency component between a high-frequency component having a frequency higher than a predetermined frequency and the low-frequency component having a frequency lower than the predetermined frequency. A demodulation unit demodulates the high-frequency component. A filter circuit passes, in the current signal, the high-frequency component from a current output unit to the demodulation unit, and causes the low-frequency component to flow from the current output unit to a predetermined reference potential point.

A reception apparatus (10) includes plural antennas (101, 102) that are compatible with an LTE communication scheme and one reception processing section (100) processing a reception signal acquired by any one of the plural antennas (101, 102).

A receiving device includes: a frequency mixer that converts a frequency of a reception signal to a baseband; an envelope demodulator; an upper sideband demodulator; and a lower sideband demodulator. Each of the envelope demodulator, the upper sideband demodulator and the lower sideband demodulator demodulates an output from the frequency mixer. The receiving device further includes: a first adder that adds an output from the envelope demodulator and an inverted output obtained by inverting an output from the upper sideband demodulator; a second adder that adds the output from the envelope demodulator and an inverted output obtained by inverting an output from the lower sideband demodulator; and a third adder that adds the output from the envelope demodulator, an inverted output obtained by inverting an output from the first adder, and an inverted output obtained by inverting an output from the second adder, to output a demodulation signal.

A method of pre-compensating for transmitter in-phase (I) and quadrature (Q) mismatch (IQMM) may include sending a signal through an up-converter of a transmit path to provide an up-converted signal, determining the up-converted signal, determining one or more IQMM parameters for the transmit path based on the determined up-converted signal, and determining one or more pre-compensation parameters for the transmit path based on the one or more IQMM parameters for the transmit path. In some embodiments, the up-converted signal may be determined through a receive feedback path. In some embodiments, the up-converted signal may be determined through an envelope detector.

A mixer includes a load portion connected between an input terminal of a first power voltage and an output terminal of the radio frequency transmit signal and configured to adjust a magnitude of the radio frequency transmit signal, a first switching unit connected to an output terminal of the radio frequency transmit signal, and configured to perform a first switching operation in response to a plurality of local oscillation signals, and a second switching unit connected between the first switching unit and an input terminal of a second power voltage, lower than the first power voltage, and configured to perform a second switching operation in response to a plurality of baseband signals, the plurality of local oscillation signals include an I+ baseband signal, an I− baseband signal, a Q+ baseband signal, and a Q− baseband signal, and the second switching unit includes a first branch performing a switching operation under control of the I+ baseband signal and the Q+ baseband signal, a second branch performing a switching operation under control of the I− baseband signal and the Q− baseband signal, a third branch performing a switching operation under control of the Q+ baseband signal and the I− baseband signal, and a fourth branch performing a switching operation under control of the Q− baseband signal and the I+ baseband signal.

A mixer includes a load portion connected between an input terminal of a first power voltage and an output terminal of the radio frequency transmit signal and configured to adjust a magnitude of the radio frequency transmit signal, a first switching unit connected to an output terminal of the radio frequency transmit signal, and configured to perform a first switching operation in response to a plurality of local oscillation signals, and a second switching unit connected between the first switching unit and an input terminal of a second power voltage, lower than the first power voltage, and configured to perform a second switching operation in response to a plurality of baseband signals, the plurality of local oscillation signals include an I+ baseband signal, an I− baseband signal, a Q+ baseband signal, and a Q− baseband signal, and the second switching unit includes a first branch performing a switching operation under control of the I+ baseband signal and the Q+ baseband signal, a second branch performing a switching operation under control of the I− baseband signal and the Q− baseband signal, a third branch performing a switching operation under control of the Q+ baseband signal and the I− baseband signal, and a fourth branch performing a switching operation under control of the Q− baseband signal and the I+ baseband signal.