Telefonaktiebolaget Lm Ericsson (Publ)

Ericsson Gmbh

Wandel & Goltermann Ate Systems Ltd.

Randall Glenn Bright

Henrik Nyberg

John Mitten

John Mark Freeze

Peter H Jansen

Tomas &Ouml;stman

Vijay K Nagaraj

A transmit circuit reduces undesired amplitude modulation (AM) in transmit signal pulses by substituting predetermined amplitude information for actual pulse amplitude information during portions of the pulse corresponding to nominally constant amplitudes. For example, GMSK and certain other modulation formats use a desired transmit pulse shape that includes a nominally flat middle portion. An exemplary AM reduction circuit detects generated pulse values corresponding to the nominally constant-amplitude portions of the transmit pulse and substitutes predetermined, preferably constant, amplitude values in their place. As such, the circuit may include a comparator used to detect the pulse values corresponding to variable amplitude portions of the pulse, which it passes through, and to detect those amplitude values corresponding to constant-amplitude portions of the pulse, which it replaces with substituted values. Such operation may include amplitude value filtering, and such operations may be modal, e.g., performed in dependence on modulation mode, etc.

Method and apparatus to reduce undesired amplitude modulation

Integrated circuit transmit modules include an integrated circuit substrate, a baseband I/Q modulator in the integrated circuit substrate that modulates an input signal to produce in-phase (I) and quadrature (Q) baseband modulated inputs, and a built-in self-test (BIST) module in the integrated circuit substrate that monitors the I and Q baseband modulated outputs, to determine whether the baseband I/Q modulator is operating properly. The BIST module generates test input data for the baseband I/Q modulator. Alternatively or in addition, the BIST module can monitor the I and Q baseband modulated outputs in response to a communications input signal from a digital signal processor. The BIST module can generate a status signal to indicate whether the baseband I/Q modulator is operating properly. The BIST module includes a first filter that is responsive to the input signal to produce a filtered input signal and a second filter that is responsive to the I and Q baseband modulated outputs, to produce a filtered output signal. A compare module compares the filtered input signal and the filtered output signal. A phase and amplitude adjuster adjusts the phase and/or amplitude of the output of the first filter. Accordingly, modulators are tested prior to and/or during field use.

Built-in self-test systems and methods for integrated circuit baseband quadrature modulators

An air frame synchronisation signal is transmitted as a data signal over a PCM link from a central unit to a plurality of remote radio transceivers, allowing the remote radio transceivers to recreate the AFS signal with the desired accuracy, compensating for transmission delays.

Telecommunications system

In order to test the functional and parametric characteristics of a unit without overloading a host computer, the host computer downloads a testing program to a plurality of digital signal processor modules which do all of the functional environmental emulation data generation and analysis of the data received from the unit under test. A reconfigurable application interface module is also programmed at the same time as the digital signal processor modules and is thus configured to accept basic emulation data generated by the digital signal processor modules and convert those data to the data environment that the unit under test is expected to experience in use. The application interface module also converts the data received from the unit under test into a format that the digital signal processor modules can analyze, the results of which analysis are made available to the host computer.

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Pittsboro, NC, United States of America

Randall Glenn Bright