Voltage-controlled oscillator

About: Voltage-controlled oscillator is a research topic. Over the lifetime, 23896 publications have been published within this topic receiving 231875 citations. The topic is also known as: VCO.

A 900 MHz local oscillator using a DLL-based frequency multiplier technique for PCS applications

Abstract: One approach to implementation of low-phase-noise integrated fixed-frequency local oscillators (LOs) for use as the RF LO in a blockdown-convert receiver architecture for PCS wireless communications down-converts the entire RF band to a lower frequency using a fixed-frequency LO. This allows new approaches to the implementation of low-phase-noise oscillators with low-Q components. The technique uses a DLL-based frequency multiplier to synthesize a RF LO whose phase noise is closely related to that of the reference crystal and not dependent on the phase noise of a VCO. An experimental prototype generates a 900 MHz signal and is designed to meet the requirements of the IS-137 standard. The device achieves a phase noise of -123dBc/Hz at a 60 kHz offset frequency with 39 mA overall current consumption from a 3.3 V supply. This prototype was fabricated in 0.35 /spl mu/m double-poly five-metal CMOS.

Charge pump with perfect current matching characteristics in phase-locked loops

Abstract: Conventional CMOS charge pump circuits have some current mismatching characteristics. The current mismatch of the charge pump in the PLLs generates a phase offset, which increases spurs in the PLL output signals. In particular, it reduces the locking range in wide range PLLs with a dual loop scheme. A new charge pump circuit with perfect current matching characteristics is proposed. By using an error amplifier and reference current sources, one can achieve a charge pump with good current matching characteristics. It shows nearly perfect current matching characteristics over the whole VCO input range, and the amount of the reference spur is <-75 dBc in the PLL output signal. The charge pump circuit is implemented in a 0.25 /spl mu/m CMOS process.

Doppler radar system for automotive vehicles

Abstract: A continuous wave Doppler radar system having a transmitter module and a receiver module is provided for automotive vehicles. Each module includes an antenna system, including a horn, a lens, and a waveguide system, which is attached to a monolithic microwave integrated circuit (MMIC) chip that provides all necessary electronic functions. Each MMIC chip may be attached to a metal base heat sink, which may be conveniently connected to a base plate heat sink that holds the entire radar assembly. The transmitter module includes a voltage controlled oscillator (VCO) that generates a VCO frequency signal which is amplified and switched sequentially to three multiplier chains for transmission in three different directions. Each transmit signal is taken off the MMIC chip by a dielectric waveguide and directed to the antenna system. The receiver module includes three receivers that are selected sequentially to provide a beam azimuth scanning function. A reference local oscillator is provided at the VCO frequency by electromagnetic radiative coupling from the VCO of the transmitter module. Information on the location and relative speed of a radar target are obtained by comparing the frequency of the signal reflected by the target with the frequency of the signal radiated by the transmitter module. Quadrature mixers are used for each receiver channel to output low frequency data signals containing amplitude and phase information on the received reflected signal. Radar directional discrimination is achieved by sequential selection of the mixer output signals.

Constant output electrosurgical unit

Abstract: An electrosurgical unit which provides a voltage output to a load An oscator in the unit produces the output of a given frequency A switching circuit coupled to the oscillator provides an unmodulated RF carrier from the oscillator for use in cutting procedures and a pulse modulated RF voltage from the oscillator for use in coagulation procedures A feedback circuit is coupled from the output to the input of the oscillator to maintain the output voltage level from the unit at a substantially constant value independent of the load

A CMOS 210-GHz Fundamental Transceiver With OOK Modulation

Abstract: This paper presents a 210-GHz transceiver with OOK modulation in a 32-nm SOI CMOS process (fT/fmax= 250/320 GHz). The transmitter (TX) employs a 2 × 2 spatial combining array consisting of a double-stacked cross-coupled voltage controlled oscillator (VCO) at 210 GHz with an on-off-keying (OOK) modulator, a power amplifier (PA) driver, a novel balun-based differential power distribution network, four PAs, and an on-chip 2 × 2 dipole antenna array. The noncoherent receiver (RX) utilizes a direct detection architecture consisting of an on-chip antenna, a low-noise amplifier (LNA), and a power detector. The VCO generates measured -13.5-dBm output power, and the PA shows a measured 15-dB gain and 4.6-dBm Psat. The LNA exhibits a measured in-band gain of 18 dB and minimum in-band noise figure (NF) of 11 dB. The TX achieves an EIRP of 5.13 dBm at 10 dB back-off from saturated power. It achieves an estimated EIRP of 15.2 dBm when the PAs are fully driven. This is the first demonstration of a fundamental frequency CMOS transceiver at the 200-GHz frequency range.