IF Amplifier Research Articles

TV sound IF amplifier with integrated circuits : E. A. Kilian, Radio Mentor Electron.35, No. 4, April (1969), p. 227. (In German.)

TV sound IF amplifier with integrated circuits : E. A. Kilian, Radio Mentor Electron.35, No. 4, April (1969), p. 227. (In German.)

RFI measurements at UHF on a pulsed plasma thruster

E Pulsed Plasma Thrusters (PPT) were flown aboard the Lincoln Experimental Satellite LES-6 to provide the thrust necessary for a stationkeeping experiment. The thrusters were manufactured by FairchildHiller, Republic Division, and provided an approximate 6 jidb-sec impulse from each discharge of 1.85 joules of electrical energy. A Radio-frequency interference (RFI) specification was drawn up along with a measurement procedure. The RFI specification, measurement procedure, and measured results are the subjects of this Note. The thruster nozzle and teflon propellent subsystem are described in Ref. 1. Thrust from the PPT was provided by the acceleration of gaseous ionized teflon through a nozzle (horn). The igniter plug initiated a conductive discharge between the anode and cathode which vaporized and ionized some of the teflon fuel element. The ionized particles were accelerated by two mechanisms, one being the gas pressure difference between the ionized particles and freespace and the other due to magnetic forces set up by the conduction current. The process is inherently noisy and thus arises the concern over RFI effects on the rf transponder aboard. The rf transponder operated at an assigned uplink frequency in the neighborhood of 300 MHz with a 100 kHz bandwidth. The receiver contained a bandpass limiting IF amplifier that had approximately 60 db of dynamic range and limited on front end input noise. Receive signals equal in power to the total threshold noise power would capture approximately one-half of the downlink transmit power.

Infrared 10.6-µm photodiode heterodyne detection

Expressions are given for heterodyne noise equivalent power, conversion gain, and frequency response in terms of diode parameters, local oscillator power, and IF amplifier noise factor. Experimental results are reported on heterodyne detection at 10.6 µm in a reverse-biased HgCdTe photodiode.

FM IF Filter Design with Group Delay and Amplitude Response Considerations

Linear phase 10.7 MHZ IF amplifier filters can offer many advantages such as lower and improved stereo multiplex performance over tose having a rectangular response characteristic. Design procedures, possibilities for filter grouping and experimental results with Linear Phase and Butterworth filters are presented. Designs are oriented toward using readily available low cost components.

Design of Efficient Broadband Variolossers

This paper describes new variolosser circuits which are suitable for use in high quality broadband IF amplifiers operating at several hundred MHz, and offering substantial improvements in power consumption, temperature stability, bandshape stability, minimum attenuation and attenuation range. Three variolossers of this type are used in the automatic gain control for the IF amplifier used in the short hop radio system experiment. We present an analysis, a design procedure, and extensive measurements. As an example of the performance to be expected, one experimental vario-loser has a minimum attenuation of 1.35 dB, a maximum attenuation of 19.5 dB, and is flat to ±0.15 dB over a 40 percent band centered at 300 MHz.

A monolithic integrated sound IF amplifier for TV sets : H. Keller, R. Paulin and O. Dietrich, Radio Mentor Electron.35, No. 1, January (1969), p. 35

A monolithic integrated sound IF amplifier for TV sets : H. Keller, R. Paulin and O. Dietrich, Radio Mentor Electron.35, No. 1, January (1969), p. 35

Design and Construction of Frequency Converter and IF Amplifier for a Microwave Relay Receiver for TV Transmission

General properties of microwave links are discussed. Frequency conversion with 4000 Mc/s. carrier to an IF of 70 Mc/s. and the corresponding IF amplifier design are given. Measurements on the unit built are discussed.

A Noise Figure Lower Bound and a Frequency Converter

This article establishes a lower bound for the noise figure of two networks in cascade. This is illustrated by means of a passive low-level frequency converter which utilizes a back diode as a nonlinear conductance. Other investigators have analyzed the properties of low-level frequency converters. However, the greatest lower bound of a combination of the converter and intermediate frequency amplifier system was not considered previously and is the subject of this paper. Knowledge of this lower bound has practical significance because if a measured value of noise figure is less than this lower bound, it follows that the measurement is in error. For illustrative purposes a lower bound is established on one of the highest quality systems available, employing a special General Electric diode as a frequency converter for the first network, and a 60 MHz IF amplifier for the second network. This resulted in a noise figure lower bound of 3.86 db for the overall system. This paper shows how this lower bound was obtained. Also the controversial right angle diode characteristic is found to be undesirable from an impedance viewpoint.

A high-performance monolithic IF amplifier incorporating electronic gain control

A direct-coupled monolithic IF amplifier that incorporates an active gain control stage and exhibits a power gain of 50 dB and an AGC range of 60 dB at 50 MHz is described. This circuit has negligible change in either input or output admittance, and has excellent signal linearity over the full range of gain control. Experimental and theoretical analyses are made of the large signal response, stability, available gain, and noise behavior of the circuit. An application to color television is discussed in which the functions of the 45-MHz IF amplifier and the dc-AGC circuitry are fabricated on a single die.

IF Amplifier using C/SUB c/ compensated transistors

An integrated bridge network of four transistors is used as a self-neutralized active element in tuned RLC amplifier designs. The bridge network compensates for the transistor collector-base junction capacitance (C/SUB c/), yielding a 95-percent reduction in the common-emitter reverse transmission admittance. IF amplifier stages that achieve the maximum unilateral power gain of a common-emitter transistor while maintaining excellent alignability are realized using the C/SUB c/ compensated transistor structure. Variations of the relative bias current levels of the transistors in the bridge network provides gain control by way of signal cancellation. This technique produces minimal frequency response variations of the amplifier stage being controlled. A noise analysis shows output signal to noise ratio at maximum attenuation can be a performance limitation.

First and Second Passage Times of Sine Wave Plus Noise

This paper is concerned with the first and second passage times of a stationary random process, I(t, a), consisting of a sinusoidal signal of amplitude (2a)1/2 plus stationary Gaussian noise with a finite expected number of zeros per unit time. This type of random process is present at the output of the IF amplifier of a radio or radar receiver during the reception of a sinusoidal signal immersed in Gaussian noise. Approximate integral equations are developed whose solutions yield approximate proba-ability densities concerning the first and second passage times of I(t, a). The resulting probability functions are presented in graphs for the case when the frequency of the sine wave is located in the center of a band of noise. Related results concerning the approximate distribution function of the absolute minimum or absolute maximum of I(t, a) in the closed interval [0, τ] are also presented.

A Differential Dual Integrated Circuit Video If with Built-in AGC for Color Television

This paper explains a new video IF amplifier for color television incorporating a high performance integrated circuit and a discrete output transistor. The integrated circuit (XC1352P) functions in two capacities: first as a unilateralized 50db gain IF amplifier with 65db usable AGC range; and second as a gated keyer and AGC amplifier with delayed AGC output for the tuner. The discrete transistor (MPS6544) with low Cre; functions as an un-neutralized output stage driving the detectors. Overall sensitivity is 250μV rms at 44MHz for 3V detected output (70db power gain). Admittance variations with AGC are negligible, leaving the in-channel pass band and adjacent channel rejection independent of AGC. The above characteristics indicate that video IF amplifiers superior to those used today can be made by incorporating both the XC1352P and MPS6544. Encapsulation of the dual function integrated circuit in a single 14 pin dual in-line plastic package will bring the overall cost of these functions down to competitive prices.

X-Band Integrated Circuit Mixer with Reactively Terminated Image

An X-band mixer using GaAs Schottky barrier diodes with a thin-film 500-MHz IF preamplifier was developed using hybrid microwave integrated circuit techniques. The balanced mixer had filters to provide a short circuit at the image frequency. The entire mixer preamplifier occupied an area of only 0.38 square inches and had a noise figure of 6.7 dB which corresponded quite closely to the theoretical noise figure considering all losses. The thin-film IF amplifier alone had a 2.2-dB noise figure and the mixer IF amplifier coupling network had a loss of 0.4 dB.

X-band integrated circuit mixer with reactively terminated image

An X -band mixer using GaAS Schottky barrier diodes with a thin-film 500-MHz IF preamplifier was developed using hybrid microwave integrated circuit techniques. The balanced mixer had filters to provide a short circuit at the image frequency. The entire mixer preamplifier occupied an area of only 0.38 square inches and had a noise figure of 6.7 dB which corresponded quite closely to the theoretical noise figure considering all losses. The thin-film IF amplifier alone had a 2.2-dB noise figure and the mixer IF amplifier coupling network had a loss of 0.4 dB.

X-Band Integrated Circuit Mixer with Reactively Terminated Image

An X-band mixer using GaAs Schottky barrier diodes with a thin-film 500-MHz IF preamplifier was developed using hybrid microwave integrated circuit techniques. The balanced mixer had filters to provide a short circuit at the image frequency. The entire mixer preamplifier occupied an area of only 0.38 square inches and had a noise figure of 6.7 dB which corresponded quite closely to the theoretical noise figure considering all losses. The thin-film IF amplifier alone had a 2.2-dB noise figure and the mixer IF amplifier coupling network had a loss of 0.4 dB.

Utilizing the IF amplifier of the ?Avangard? installation for receiving the 100 kHz signal of the RES radio station

Utilizing the IF amplifier of the ?Avangard? installation for receiving the 100 kHz signal of the RES radio station

Some Considerations of Broadband Noise Performance of Optical Heterodyne Receivers

We derive an explicit expression in this paper for the spot noise factor of a perfectly aligned optical heterodyne receiver consisting of a semiconductor photodiode followed by an IF amplifier. We show that this noise factor F <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</inf> , which is a function of the admittance of the diode, varies as a function of the modulation frequency. We obtain constraints imposed by the photodiode on the broadband noise performance of the optical receiver for any arbitrary lossless interstage network. The integral form of the constraint shows that the noise factor F <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</inf> cannot be made equal to its optimum value F <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RO</inf> over any nonzero band of frequencies. We give explicit expressions for the amount of tolerance of broadband noise performance obtained with lossless interstage networks. We show that for certain types of approximations, and for a certain transistor IF amplifier usually used in practice, the interstage network which achieves broadband signal performance for the receiver also obtains broadband noise performance. The theory of broadband noise performance we present for optical heterodyne receivers can also be applied to the study of broadband noise performance of other linear systems normally encountered in practice.

140-MHz main IF amplifiers for 2700-channel microwave repeaters

This report presents the circuit configuration and performance of a 140-MHz main IF amplifier satisfying the specifications for 2700- channel microwave repeaters.

Noise Figure and Conversion Loss of the Schottky Barrier Mixer Diode

The theory of mixer operation is briefly reviewed and the results presented in graphical form convenient to the designer. In particular, the minimum noise figure, conversion loss, and the source and output impedances are plotted as functions of the pulse duty ratio of the diode current. Emphasis is placed on the pulse duty ratio as a more fundamental parameter for defining mixer operation than the magnitude of the diode voltage which is generally nonsinusoidal. It is shown that Schottky diode mixers should exhibit single sideband noise figures as low as 3 dB at X band when used in conjunction with 1.5 dB noise figure IF amplifiers, provided the diodes have cutoff frequencies higher than 500 GHz.

An Approximate Nonlinear Analysis of Tunnel-Diode Converters

Approximate analyses published previously on tunnel-diode converters are basically phenomenological in nature by restricting the currents flowing through the tunnel diode or (and) the voltage across it to the signal, local oscillator, and intermediate frequencies only. Because of the nonlinear nature of the tunnel diode, many higher-order frequency components corresponding to harmonics and products, sums, and differences of the above mentioned frequencies are present. By including the effects of series resistance and series inductance and restricting the operating region within the parabolic portion of the tunnel-diode characteristics, the present analysis attempts to formulate the problem in a rigorous manner through the derivation of a second-order nonautonomous nonlinear differential equation with time-varying coefficients. The solution to a first-order approximation is obtained by incorporating a variational type treatment with an expansion type perturbation method. In an effort to verify the validity of the theoretical results obtained by the nonlinear analysis, an analog simulation is carried out since the control of required parameters in actual experiments is extremely difficult, especially in the microwave frequency region. The general agreement between the theoretical results and the analog simulation is promising and, therefore, should yield enough information to facilitate the control and adjustment of the various parameters in actual experiments especially in the microwave region. Specifically, we have verified by the analog simulation the theoretical prediction that the optimized conversion gain is obtained when the source resistance is about one third of the load resistance. In addition to minimizing the converter noise, the noise due to the first IF amplifier can also be minimized by selection of the correct converter load resistance by using Figs. 4 throngh 8.