Sierra Wireless, Inc.

J F Beaudoin

Ronald John Vanderhelm

Marek Karol Dutkiewicz

Gregory John Funk

A radio-frequency output signal having a specified characteristic is produced using a combination of a calibrated radio unit in which a calibration factor is stored and an uncalibrated modem unit. The calibration factor is input to the modem unit from the radio unit, and the modem outputs to the radio unit a signal of a nominal signal level determined in accordance with the calibration factor. An actual signal level of the signal is measured, and a gain factor within the modem unit is adjusted until the nominal signal level and the actual signal level are substantially equal. A wireless modem includes a calibrated radio unit and an uncalibrated modem unit coupled to the radio unit. A first signal path is provided from the modem unit to the radio unit, and a feedback signal path from the radio unit to the modem unit. The modem unit includes control circuitry for outputting across the first signal path a signal that is nominally of a desired signal level, and for adjusting a nominal signal level of the signal in accordance with information received across the feedback signal path.

Modulation signal calibration between modem and radio using loopback

An integrated circuit card, such as PC Card, is provided in which a step-down converter in the form of a switching regulator provides a stable operating voltage at increased current beyond what is normally available from a single source. In particular, a quiet and stable power supply is obtained by modifying the standard configuration of a switching regulator such that the catch diode, or free-wheeling diode, instead of being connected to ground at the non-blocking terminal, is connected to a primary voltage source approximating the desired output voltage. If the desired output voltage is 5V, for example, the catch diode may be connected to Vcc supplied by a PC Card slot, which nominally supplies 5V. The block terminal of the catch diode is connected through the switch of the switching regulator to a higher, supplementary, voltage source, e.g. Vpp=12V in the case of a PC Card slot. During operation of the integrated circuit card at lower power levels, the primary voltage source is able to supply substantially all of the required power, such that the switch of the switching regulator may remain predominantly open, minimizing switching noise. During operation of the integrated circuit card at higher power levels, the switching regulator boosts the output voltage just enough to compensate for voltage droop. The integrated circuit card is therefore supplied with a stable, low-noise source of power.

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Surrey, Canada

J F Beaudoin