Rohde and Schwarz Gmbh & Co. Kg

Thomas Maucksch

Uwe Baeder

Gottfried Holzmann

Werner Mittermaier

Uwe Bäder

Frank Korber

Erwin Biebl

A method for testing the error ratio BER of a device under test against a specified allowable error ratio comprises the steps: measuring ns samples of the output of the device, thereby detecting ne erroneous samples of these ns samples, defining BER(ne)=ne/ns as the preliminary error ratio and deciding to pass the device, if the preliminary error ratio BER(ne) is smaller than an early pass limit EPL(ne). The early pass limit is constructed by using an empirically or analytically derived distribution for a specific number of devices each having the specified allowable error ratio by separating a specific portion DD of the best devices from the distribution for a specific number of erroneous samples ne and proceeding further with the remaining part of the distribution for an incremented number of erroneous samples.

Method for testing the error ratio BER of a device according to confidence level, test time and selectivity

A method for performing a statistical test on a device or radio channel, which has N outcomes in the form of N different events, whereby N is higher than two, with the following steps:

Method to perform a statistical test in which the experiment is multinomial

A method for testing the (Bit) Error Ratio BER of a device against a maximal allowable (Bit) Error Ratio BERwith an early pass and/or early fail criterion, whereby the early pass and/or early fail criterion is allowed to be wrong only by a small probability F for the entire test. Ns bits of the output of the device are measured, thereby ne erroneous bits of these ns bits are detected. PDand/or PDare obtained, whereby PDis the worst possible likelihood distribution and PDis the best possible likelihood distribution containing the measured ne erroneous bits with a single step wrong decision probability D, which is smaller than the probability F for the entire test. The average numbers of erroneous bits NEand NEfor PDand PDare obtained. NEand NEare compared with NE=BERns. If NEis higher than NEor NEis lower than NEthe test is stopped. Sequential sampling with two one-tailed parametric hypothesis test for the poisson distribution.

Method for testing the error ratio of a device using a preliminary probability

A method for testing the (Bit) Error Ratio BER of a device against a maximal allowable (Bit) Error Ratio BERwith a early pass and/or early fail criterion, whereby the early pass and/or early fail criterion is allowed to be wrong only by a small probability D. ns bits of the output of the device are measured, thereby ne erroneous bits of the ns bits are detected. PDand/or PDare obtained, whereby PDis the worst possible likelihood distribution and PDis the best possible likelihood distribution containing the measured ne erroneous bits with the probablility D. The average numbers of erroneous bits NEand NEfor PDand PDare obtained. NEand NEare compared with NE=BER&#xd7;ns. If NEis higher than NEor NEis lower than NEthe test is stopped.

Method for testing the error ratio of a device

A method for testing the time delay error ratio ER of a device against a maximal allowable time delay error ratio ERwith an early pass and/or early fail criterion, whereby the early pass and/or early fail criterion is allowed to be wrong only by a small probability D. ns time delays TD of the device are measured, thereby ne bad time delays of these ns time delays TD are detected. PDand/or PDare obtained, whereby PDis the worst possible likelihood distribution and PDis the best possible likelihood distribution containing the measured ne bad time delays with the probability D. The average numbers of erroneous bits NEand NEfor PDand PDare obtained. NEand NEare compared with NE=ERns. If NEis higher than NEor NEis lower than NEthe test is stopped.

Method to evaluate whether a time delay is better than a time limit

The invention concerns a method to evaluate whether a statistical time delay (TD) between a first event and a second event of a device under test is better than a test limit (TL). The method includes the steps: performing a minimum number N of tests and evaluating the time delay (TD) from each test; modeling a first probability distribution (P) of the evaluated time delays (TD); obtaining a second probability distribution (P) of the evaluated time delays (TD); performing a statistical transformation in order to obtain a third probability distribution (P) of the evaluated time delays (TD); and deciding to pass the device under test, if a certain percentage of the area of the third probability distribution (P) is on a good side (GS) of the test limit (TL).

Time delay evaluation

For generating an RF signal modulated by a message and distorted by a predetermined fading profile for testing RF receivers, a sequence of digital phase and amplitude values which corresponds to the message modulation is arithmetically processed by a predetermined fading profile and stored in memory, and an RF carrier is amplitude and phase modulated by the stored values to produce a testing signal for the RF receivers.

Method of generating an RF signal modulated by a message signal and

A sine-wave oscillator produces a sine-wave signal of a digitally predetermined frequency f in successive steps by only one multiplication and one addition under control by a clock generator having a clock frequency p. During a first step the value A.sub.(i+l) =A.sub.i +B.sub.i .multidot.k is determined and during a subsequent second step the value B.sub.(i+l) =B.sub.i -A.sub.(i+l) .multidot.k is determined therefrom, A.sub.(i+l) and B.sub.(i+l) being the respective newly calculated values, A.sub.i and B.sub.i being the respective previous values calculated in a preceding step, and k being a factor k=2.multidot.sin (.pi..multidot.f/p) calculated in a computer. The period of the successive steps is selected to be 1/2 p, and for the first step A.sub.(o) =0 and B.sub.(o) =cos (.pi..multidot.f/p) are selected. At least one of the two factors A.sub.(i+l) and B.sub.(i+l) is finally converted to an analog sine-wave signal in a digital-to-analog converter.

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Tuntenhausen, Germany

Thomas Maucksch