Frequency feedback phase-locked oscillator†

Locking phenomena as well as the phase following behaviour of a type of phase-locked oscillator (PLO) called frequency feedback phase-locked oscillator (FFPLO) have been studied in detail. Expressions for the locking range and the signal handling capacity when it is tracking an TTM signal have been derived. Stability of the system has been discussed with the help of a dual Nyquist plot. Experimental performance of the system with regard to the reception of a single tone FM signal is quite satisfactory and has been found to be in agreement with the theoretical predictions.     

A new type of transistorized frequency meter†

The paper describes the design and construction of a new type of frequency meter. In the present instrument the important characteristic of a monostable circuit changing its state by an input impulse signal has been utilized for measuring the frequency of the input signal

The instrument covers a frequency span from 10 Hz to 10 kHz in three separate ranges, with a linear scale of indication. A permanent magnet moving coil type sensitive motor has been used as the indicating element. A consistency of better than 1 % has been obtained between the calibrations of the three ranges using the same scale. The authors fuel that they have been able to offer a novel frequency meter of good resolution, wide frequency coverage and rugged construction. The instrument requires no special maintenance skill.     

A linear theory and design study for a gyrotron backward-wave oscillator†

A linear theory for a gyrotron backward-wave oscillator (gyro-BWO) is developed. The theory solves a reduced one-dimensional Maxwell-Vlasov equation in the form of a linear integro-differential equation using the Laplace transformation. The relative amplitudes among the waveguide modes and beam modes are completely determined and enable one to calculate gyro-BWO start-oscillation conditions. Using this analysis and including velocity spread effects, a design of a millimetre-wave gyro-BWO has been carried out based on the operating parameters of an existing electron gun. Tunability over a range of 86 GHz to 103 GHz is predicted with output power estimated to be ～ 1 kW.     

Matrix synthesis of harmonic oscillator circuits †

A synthesis method is given for oscillators of the type that may be represented as a single two-port network with a transmission matrix [T]=[A, B;C, D] having its output fed directly back to its input, thereby imposing the condition:

A+D?Δ?1=0,

where ΔΞAD? BC. To obtain sustained oscillation at a single real frequency ω₀ this condition is interpolated at ω₀ by a polynomial equation in s. By identifying the two equations a set of functional values may be obtained for the [T] matrix elements. Four sots of basic circuit are developed in detail from the quadratic or cubic polynomial equation, with Δ = 0 or Δ≠0. Those having Δ = 0 arc well-known forms, but those with Δ =0 are novel.     

A millimeter wave linear superposition oscillator in 0.18 μm CMOS technology

This paper presents a millimeter wave （mm-wave） oscillator that generates signal at 36.56 GHz. The ram-wave oscillator is realized in a UMC 0.18 μm CMOS process. The linear superposition （LS） technique breaks through the limit of cut-off frequency （JET）, and realizes a much higher oscillation than Jr. Measurement results show that the LS oscillator produces a calibrated 37.17 dBm output power when biased at 1.8 V; the output power of fundamental signal is -10.85 dBm after calibration. The measured phase noise at 1 MHz frequency offset is -112.54 dBc/Hz at the frequency of 9.14 GHz. This circuit can be properly applied to mm-wave communication systems with advantages of low cost and high integration density.     

Cut-off frequency of a heterojunction transistor†

Indiffusion of impurities into a semiconductor takes place at high temperatures. In the case of hotorojunction transistors, tho impurity concentration on the emitter side of the base approaches or even exceeds the intrinsic concentration of electrons and holes at the temperature of impurity indiffnaion. As a result, the profile of impurity concentration in the base is not the complementary error function for an infinite source. This is duo to field-aided diffusion by ionized impurities resulting in a variable diffusion coefficient for such impurities.     

Ultra low power frequency divider for 2.45 GHz ZigBee frequency synthesizer

An ultra low power CMOS frequency divider whose modulus can be varied from 481 to 496 is presented. It has been customized to be used in 2.45 GHz Integer-N PLL frequency synthesizers utilized in ZigBee standard. Its based on swallow divider that replaces the swallow counter by a simple digital circuit in order to reduce power consumption and design complexity. Also a low power and high speed divide-by-7/8 is presented. Post layout simulation results exhibit 420 μW power consumption for 4 bit frequency divider in 2.45 GHz ISM frequency band that proves 40 % reduction compared to same previous works. All of the circuits have been designed in 0.18 μm TSMC CMOS technology with a single 1.8 V DC voltage supply.     

A 2.7–6.1 GHz CMOS local oscillator based on frequency multiplication by 3/2

Frequency multiplication by 3/2 is proposed as a means to expand the frequency generation capabilities of a single LC VCO. Fractional frequency multiplication is obtained by cascading a broadband injection locked modulo-two divider and a multiply-by-three circuit based on edge combining. The proposed solution is inductorless, thus very compact. It allows the generation of all frequencies from 2.7 to 6.1 GHz with a performance suitable for cellular standards. It shows a phase noise floor below ?150 dBc/Hz and a spurious level below ?35 dBc. The multiplier by 3/2 consumes 5 mA and the VCO draws 10 mA from a 1.2 V supply. The additional power consumption due to the multiplier trades with the small area penalty and the flexibility of this solution, compared to the use of multiple LC VCOs.     

Macro cellular network transition from traditional frequency range to 28 GHz millimeter wave frequency band

The target of this article is to analyze the impact of transition from cellular frequency band i.e. 2.1 GHz to Millimeter Wave (mmWave) frequency band i.e. 28 GHz. A three dimensional ray tracing tool “sAGA” was used to evaluate the performance of the macro cellular network in urban/dense-urban area of the Helsinki city. A detailed analysis of user experience in terms of signal strength and signal quality for outdoor and indoor users is presented. Indoor users at different floors are separately studied in this paper. It is found that in spite of considering high system gain at 28 GHz the mean received signal power is reduced by almost 16.5 dB compared with transmission at 2.1 GHz. However, the SINR is marginally changed at higher frequency. Even with 200 MHz system bandwidth at 28 GHz, no substantial change is witnessed in signal quality for the outdoor and upper floor indoor users. However, the users at lower floors show some sign of degradation in received signal quality with 200 MHz bandwidth. Moreover, it is also emphasized that mobile operators should take benefit of un-utilized spectrum in the mmWave bands. In short, this paper highlights the potential and the gain of mmWave communications.     

A transistorized electronic stimulator†

This paper describes the design of an economical transistorized stimulator suitable for use by students in physiological studies, as well as in research applications. The repetition rate, pulse duration and magnitude of the output pulse are individually selectable by range and by variable fine control within each range. The instrument has been designed with completely indigenous components.     

A 55 nm CMOS △∑fractional-N frequency synthesizer for WLAN transceivers with low noise filters

A fully integrated ΔΣ fractional-N frequency synthesizer fabricated in a 55 nm CMOS technology is presented for the application of IEEE 802.11b/g wireless local area network(WLAN) transceivers.A low noise filter,occupying a small die area,whose power supply is given by a high PSRR and low noise LDO regulator,is integrated on chip.The proposed synthesizer needs no off-chip components and occupies an area of 0.72 mm2 excluding PAD.Measurement results show that in all channels,the phase noise of the synthesizer achieves -99 dBc/Hz and -119 dBc/Hz in band and out of band respectively with a reference frequency of 40 MHz and a loop bandwidth of 200 kHz.The integrated RMS phase error is no more than 0.6°.The proposed synthesizer consumes a total power of 15.6 mW.     

Control of resonant frequency of monopole aerial by resistive loading †

The resonant and anti-resonant lengths of a monopole resistively loaded at its midpoint are found as a function of the loading resistance. If this resistance is less than √Z_cc, where √Z_c is the average characteristic impedance of the monopole, the first resonant length is increased above that of the unloaded monopole, but if greater than √Z_c both the resonant and anti-resonant lengths are the same as those of an unloaded monopole having the same length as the lower section of the aerial.     

Design of a 30 GHz rotary traveling wave oscillator with improved frequency tuning range in 0.18 μm CMOS technology

In this paper, the operation of rotary traveling wave oscillators is analyzed, the general oscillation condition is derived, and analytical formula for the oscillator loss is presented. Based on this analysis, switched transmission line is employed to extend the output frequency tuning range. Post-layout simulation shows a frequency tuning range of 3.1 GHz in the vicinity of 30 GHz. The proposed half-quadrature VCO exhibits a phase noise better than −102.2 dBc/Hz at 1 MHz offset frequency. The VCO provides an output power level ranging from −6 to −2.5 dBm with drawing 15.2 mA of dc current from a 1.8 V power supply.     

A low phase noise and low power 3–5 GHz frequency synthesizer in 0.18 µm CMOS technology

A low power frequency synthesizer for WLAN applications is proposed in this paper. The NMOS transistor-feedback voltage controlled oscillator (VCO) is designed for the purpose of decreasing phase noise. TSPC frequency divider is designed for widening the frequency range with keeping low the power consumption. The phase frequency detector (PFD) with XOR delay cell is designed to have the low blind and dead zone, also for neutralizing the charge pump (CP) output currents; the high gain operational amplifier and miller capacitors are applied to the circuit. The frequency synthesizer is simulated in 0.18 µm CMOS technology while it works at 1.8 V supply voltage. The VCO has a phase noise of −136 dBc/Hz at 1 MHz offset. It has 10.2% tuning range. With existence of a frequency divider in the frequency synthesizer loop the output frequency of the VCO can be divided into the maximum ratio of 18. It is considered that the power consumption of the frequency synthesizer is 4 mW and the chip area is 10,400 µm².     

Very low Q-factor impedance measurements using a lock-in amplifier technique†

A technique for very low Q-factor impedance measurements, based on a lock-in amplifier as a vector voltmeter, is presented. Some practical details are discussed. The accuracy of the measurements has been studied by comparison, using a bridge method. As an application, the forward bias impedance of a variety of p-n junction is presented.     

A △∑ fractional-N frequency synthesizer for FM tuner using low noise filter and quantization noise suppression technique

A △∑ fractional-N frequency synthesizer fabricated in a 130 nm CMOS technology is presented for the application of an FM tuner. A low noise filter, occupying a small die area and decreasing the output noise, is integrated on a chip. A quantization noise suppression technique, using a reduced step size of the frequency divider, is also adopted. The proposed synthesizer needs no off-chip components and occupies an area of 0.7 mm2. The in-band phase noise （from 10 to 100 kHz） below -108 dBc/Hz and out-of-band phase noise of -122.9 dBc/Hz （at 1 MHz offset） are measured with a loop bandwidth of 200 kHz. The quantization noise suppression technique reduces the in-band and out-of band phase noise by 15 dB and 7 dB respectively. The integrated RMS phase error is no more than 0.48°. The proposed synthesizer consumes a total power of 7.4 mW and the frequency resolution is less than 1 Hz.     

A high frequency “divide-by-odd number” CMOS LC injection-locked frequency divider

Numerous circuit topologies have been proposed for divide-by-ρ injection-locked frequency dividers (ILFDs), most of which have been optimized for division by even numbers, especially divide-by-2. It has been more difficult to realize division by odd numbers, such as divide-by-3. In this paper we present simulations of an RF CMOS ILFD that can operate equally well in both divide-by-2 and divide-by-3 modes. The ILFD is based on a cross-coupled CMOS LC oscillator with direct injection and an auxiliary injection path. The paper presents two variants of the circuit architecture and Cadence simulations in the multi-GHz frequency range using a standard TSMC 65 nm CMOS process design kit.     

Amplitude and frequency modulation using a wide dynamic range injected-beam crossed-field gun†

Methods for amplitude modulation and frequency modulation of injected beam crossed-field tubes using a wide dynamic range crossed-field gun (Sidhu and Wadhwa 1967) are described. This gun has the property that by properly adjusting the electric fields in the two regions of the transformer section, the electron beam can be injected into the interaction region at any desired level, with a fixed injection velocity or the velocity of injection can be varied over a wide range at a fixed injection level. The properties of injection level variations and injection velocity variation can be utilized to produce amplitude modulation and frequency modulation in injected beam crossed-field tubes.

The beam is injected optimally into the interaction region as desired, without any cycloid formation under conditions of fixed magnetic field. The flexibility of the gun to give variable current and inject the beam optimally into the interaction region under the conditions of fixed magnetic field, can also be used for amplitude modulation purposes.