Abstract: A sampling circuit for sequential sampling of a broadband periodic input signal having a field effect transistor as a nonlinear component to which a pulsed-shaped sampling signal is supplied, by which sampling is activated so that an output signal is produced. In this way, a sampling circuit is attained which is economical, technically durable and which can be used in a versatile and simple manner.

Abstract: A frequency synthesizer, especially for use with a time-base generator of a fill-level meter employing the radar principle is designed to output a first frequency signal and a second frequency signal at mutually slightly different frequencies. The synthesizer incorporates a reference oscillator operating at a reference frequency and a control oscillator regulated at a control frequency. A first frequency divider with a division factor V1 is connected in line with the reference oscillator and a second frequency divider with the division factor V2 is connected in line with the control oscillator, which frequency dividers serve to output the first frequency signal and the second frequency signal, respectively. The result is a stable frequency synthesizer with a large phase-control bandwidth and consequently an extremely short transient response time as well as broad-band phase-noise suppression. A method for operating the synthesizer is also disclosed.

Abstract: A frequency synthesizer, especially for use with a time-base generator of a fill-level meter employing the radar principle is designed to output a first frequency signal and a second frequency signal at mutually slightly different frequencies. The synthesizer incorporates a reference oscillator operating at a reference frequency and a control oscillator regulated at a control frequency. A first frequency divider with a division factor V1 is connected in line with the reference oscillator and a second frequency divider with the division factor V2 is connected in line with the control oscillator, which frequency dividers serve to output the first frequency signal and the second frequency signal, respectively. The result is a stable frequency synthesizer with a large phase-control bandwidth and consequently an extremely short transient response time as well as broad-band phase-noise suppression. A method for operating the synthesizer is also disclosed.

Abstract: A method for generating short electric pulses, comprising the steps of generating a control pulse, feeding the control pulse to a bipolar transistor, which subsequently emits an output signal with a steep switch-off side by exploiting the charge storage effect of the bipolar transistor, and differentiating the output signal with the steep switch-off side so that short primary pulses are generated. An electric pulse generator is also disclosed.

Abstract: A sampling circuit for sequential sampling of a broadband periodic input signal having a field effect transistor as a nonlinear component to which a pulsed-shaped sampling signal is supplied, by which sampling is activated so that an output signal is produced. In this way, a sampling circuit is attained which is economical, technically durable and which can be used in a versatile and simple manner.

Abstract: A method for generating short electric pulses, comprising the steps of generating a control pulse, feeding the control pulse to a bipolar transistor, which subsequently emits an output signal with a steep switch-off side by exploiting the charge storage effect of the bipolar transistor, and differentiating the output signal with the steep switch-off side so that short primary pulses are generated. An electric pulse generator is also disclosed.

Abstract: A method for the processing of a frequency signal especially for utilization in the evaluation of a distance measurement by means of pulsed electromagnetic waves or of frequency-modulated continuous waves on the basis of the radar principle. The frequency signal is divided into at least two frequency ranges corresponding to two main components of the frequency signal, the frequency signal in each of the two frequency ranges is then subjected to a separate Fourier transform, the Fourier transform applied to the frequency signal in the first frequency range resulting in a corresponding first complex time signal and the Fourier transform applied to the frequency signal in the other frequency range resulting in a second complex time signal. The second time signal is complex-divided by the first time signal which produces a third time signal, and the third time signal is then subjected to a Fourier transfer, the result being a processed frequency signal.

Abstract: A method for the processing of a frequency signal especially for utilization in the evaluation of a distance measurement by means of pulsed electromagnetic waves or of frequency-modulated continuous waves on the basis of the radar principle. The frequency signal is divided into at least two frequency ranges corresponding to two main components of the frequency signal, the frequency signal in each of the two frequency ranges is then subjected to a separate Fourier transform, the Fourier transform applied to the frequency signal in the first frequency range resulting in a corresponding first complex time signal and the Fourier transform applied to the frequency signal in the other frequency range resulting in a second complex time signal. The second time signal is complex-divided by the first time signal which produces a third time signal, and the third time signal is then subjected to a Fourier transfer, the result being a processed frequency signal.

Abstract: In a network analyzer having one or two test ports each of which is connected via fourports to measuring points the measured values of which are analyzed in an evaluation means that includes a memory for storing system errors which have been determined during a calibration operation and must be taken into account for the object measurement, there is provided a calibration twoport between at least one of said test ports and said fourport of the associated measuring points, said calibration twoport being adapted to be switched from a basic state to two further switching states, and said calibration twoport differs in one of said further switching states from the basic switching state at least in transmission and in the other one of said further switching states differs at least in reflection from the basic switching state.

Abstract: In a method for calibrating a network analyzer having two test ports and at least four measuring locations according to the fifteen-term principle, correction values that are taken into consideration in the following subject measurements are calculated by successive measurement of the transmission and reflection parameters at five calibration standards that are successively connected in arbitrary sequence between the two test ports. A one-port network having a known impedance or open circuit is used as a calibration standard for the first calibration measurement. It is being successively connected to the two test ports (MM or OO double one-port network calibration) and four calibration standards are used for the other four calibration methods. Only eleven of the total of sixteen scatter parameters of these four calibration standards are known, whereas the remaining, five unknown scatter parameters are subsequently calculated from the total of measured values.

Abstract: A method calibrates a network analyzer having two test ports and at least four measuring locations by successive measurement of the transmission and reflection parameters at three calibration standards successively connected in arbitrary sequence between the two test ports according to the seven-term principle. A first calibration measurement is implemented at an electrical line whose characteristic impedance is known and whose electrical propagation constant may be unknown and complex. Second and third calibration measurements are then respectively implemented at a two-port that is connected between the test ports and is constructed of concentrated components. The electrical propagation constant of the line and correction values that are taken into consideration in following object measurements are calculated from these measured values.

Abstract: For calibrating a network analyzer having two test ports by successive measurements of the transmission and the reflection parameters on a plurality of calibration standards in any desired order, from which correction values are then calculated that are taken into account in subsequent measurements of a device-under-test, at least five successive calibration measurements with predetermined calibration standards or calibration standards in the form of discrete components according to basic predetermined circuits are performed. A total of 15 correction values is then calculated from the measured values obtained with these calibration standards.

Abstract: For calibrating a network analyzer which has two test ports adapted to be connected to an object under test by means of lines or through free-space, the transmission and reflection parameters are measured in a first calibrating measurement either on a line which is connected in reflection-free fashion between the two test ports or on the free-space connection. Subsequently two or three further calibrating measurements are performed with the same free-space connection or the same line, respectively, on calibration standards which are implemented by reflection-symmetrical and reciprocal interfering objects or discontinuities inserted at two or three different positions in the free-space connection or the line, respectively.

Abstract: In a method of calibrating a network analyzer, in which calibration measurements are performed in succession in a random sequence on several different calibration standards which are linked to the two test ports, the first calibration standard used is a two-port unit which is linked between the two test ports and of which all complex scattering parameters are known, and the further calibration standards used are three one-port units of random, though different, reflection characteristics which are successively linked to one of the two test ports, or are linked in any desired combination to both test ports.

Abstract: A multistage single-sideband shifter composed of N switchable phase shifters connected in cascade, where N is a positive integer greater than 1, each phase shifter being constructed to produce a switchable phase shift and a control unit connected to the phase shifters for switching the phase shifters chronologically successively in a selected sequence into all possible 2.sup.N combinations, for periodically repeating the selected sequence, and for chronologically reversing the selected sequence.

Abstract: Methods for establishing the complex measuring capability of homodyne operating network analyzers. Single port as well as two-port measuring devices are treated in which the signal detection takes place by means of a linear mixing process. It is possible to overcome the disadvantage of the homodyne detection process, which does not directly supply information relating to the amplitude and phase of the measurement signal, by measuring arbitrary unknown standards. The required number of different unknown standards depends, among other things, on the complexity of the measuring device used. One of the proposed methods operates without any standards at all. After weighting factors have been determined, complex measuring values can be ascertained and one can then proceed as in the case of a heterodyne network analyzer, i.e. with system error calibration measurements and finally with DUT (device under test) measurements.

Abstract: For calibrating a network analyzer, calibration measurements are successively performed in any desired order on three different calibration standards connected between the two test ports; the first calibration standard is a two-port circuit all of whose complex scatter parameters are known and which is, for example, implemented by a direct connection of the two test ports; the second calibration standard is an attenuator of random transmission but known reflection; the third calibration standard preferably is a two-port circuit exhibiting random reflection which, however, is equal on both sides and different from the reflection of the second calibration standard.

Abstract: For the reduction of noise signals, and particularly crosstalk signals, in measurement systems for analyzing emission or transmission processes and composed of a serial arrangement of a signal source (1), a measurement path (2) with or without a transmission test object (8), a detector (3), and a measurement and display circuit (5), an identification modulation is imparted to the signal component carried in the measurement path by means of repeated modulation (6, 9). The evaluation of the detector output signal may be performed with respect to a frequency which is free of the effects of the single modulation signals occurring in the detector output signal because of noise pick-up. Use of this method in homodyne systems for quadrupole parameter measurements further eliminates the effects of crosstalk reflections which typically occur in these systems.

Abstract: An amplitude ratio and phase-difference analysis can be carried out with a measured object provided with a measured branch which is divided from a reference branch from a supply oscillator. The measured branch has 2.sup.n switching combinations of phase shifters which are decoupled from one another and operated by a controller. The branches then feed a mixer and through a band-pass filter calculating circuit for determining the relative amplitude and phase which can be displayed on a register.

Abstract: Range-dependent sensitivity of an RF doppler radar apparatus is reduced to prevent false alarms when small objects move in close proximity to the apparatus' antenna. The sensitivity is reduced by periodically FM-modulating the transmitted RF signal at a frequency corresponding to a wavelength which is at least four times the operating range of the apparatus. The reflection of the transmitted signal is mixed with the transmitted signal to produce a difference frequency signal which is sampled at instants of maximum amplitude.