Samsung Electronics Co., Ltd.

Korea Electronics Technology Institute

Hae-moon Seo

Young-jin Kim

Kwang-Ho Won

Seong-Dong Kim

Young-Kuk Park

In-chul Hwang

Jae-wan Kim

Yeon-Kuk Moon

Yeon-Kug Moon

Myung-Hyun Yoon

Single sideband (SSB) mixers and methods of extracting a SSB signal, which are capable of outputting a single frequency using a plurality of mixers and a local oscillating frequency without having to implement phase-shifting. In one embodiment, a single sideband (SSB) mixer comprises a first mixer and a second mixer, wherein the first and second mixers multiply an input IF (intermediate frequency) signal by a local IF signal having the same frequency of the input IF signal; a band-pass filter which passes upper sideband signal output from the first mixer; a third mixer which multiplies the upper sideband signals output from the band-pass filter by a LO (local oscillating) signal; a fourth mixer which multiplies the signals output from the second mixer by the LO signal; and a subtraction device that subtracts output signals of the third mixer from output signals of the fourth mixer. Accordingly, a quadrature local oscillator which displaces a phase of a local oscillating signal by 90&#xb0; at a high frequency is not required. Also, since the SSB mixer applies the same local oscillating frequency signal to each mixer, the rejection characteristics against undesired signals can be achieved to a level of about 70 dB, experimentally.

Single sideband mixer and method of extracting single sideband signal

A digital intermediate frequency transmitter for a wireless communication is disclosed. In accordance with the present invention, an improvement of a modulation quality such as an EVM, a linearity and a power consumption is possible, and a main characteristic of a wireless communication transmitter may be embodied at a low cost through an integration such that a high frequency 90&#xb0; phase shifter, a voltage controlled oscillator having a 2&#xd7; frequency or higher and a high frequency I/Q local oscillated signals are not required and a side-band signal may be effectively removed.

Digital intermediate frequency transmitter for wireless communication

The present invention relates to an I/Q modulator using a current-mixing method used for a direct conversion wireless communication transmitter. In accordance with the present invention, an EVM of a wireless communication system, a linearity and a power consumption are improved by converting a D/A converted signal to a current level and then performing a frequency modulation.

I/Q modulator using current-mixing and direct conversion wireless communication transmitter using the same

An apparatus and method for receiving RF signals in a RF communication system are provided. The apparatus for receiving RF signals comprises a pre-processing unit for bandpass-filtering a signal received through an external antenna with a predetermined bandwidth and extracting a RF input signal having a desired frequency; a mixing unit for mixing the RF input signal provided from the pre-processing unit with a local oscillation signal having the same frequency as the RF input signal and generating a desired baseband signal; a noise-free-signal amplifying unit for shifting the desired baseband signal to a band that is free of effects due to 1/f noise, amplifying the shifted baseband signal, and re-shifting the amplified signal to the baseband; and a baseband processing unit for selecting a desired channel signal from the amplified baseband signal to be provided from the noise-free-signal amplifying unit and amplifying the selected signal.

Apparatus and method for receiving RF signal free of 1/f noise in radio communication system

Growing community of inventors

Yongin, South Korea

Hae-moon Seo