Abstract: An adapter/converter circuit converts transmissions by a mobile telephone built for one standard (e.g., PCS) from the telephone transmit/base station receive frequency of that one standard to the telephone transmit/base station receive frequency of another standard (e.g., cellular), and converts transmissions by a base station or similar device (e.g., a base station simulator) from the telephone receive/base station transmit frequency of the one standard to the telephone receive/base station transmit frequency of the other standard. The two frequency conversions occur simultaneously on two parallel legs under the control of a PLL dual frequency synthesizer, which is in turn controlled by user input (in the case where the adapter is used to allow, e.g., PCS telephones to be tested on cellular test equipment) or by the base station (in the case where the adapter is used to allow, e.g., PCS telephones to be used with a cellular base station).

Abstract: An adapter/converter circuit converts transmissions by a mobile telephone built for one standard (e.g., PCS) from the telephone transmit/base station receive frequency of that one standard to the telephone transmit/base station receive frequency of another standard (e.g., cellular), and converts transmissions by a base station or similar device (e.g., a base station simulator) from the telephone receive/base station transmit frequency of the one standard to the telephone receive/base station transmit frequency of the other standard. The two frequency conversions occur simultaneously on two parallel legs under the control of a PLL dual frequency synthesizer, which is in turn controlled by user input (in the case where the adapter is used to allow, e.g., PCS telephones to be tested on cellular test equipment) or by the base station (in the case where the adapter is used to allow, e.g., PCS telephones to be used with a cellular base station).

Abstract: An adapter/converter circuit converts transmissions by a mobile telephone built for one standard (e.g., PCS) from the telephone transmit/base station receive frequency of that one standard to the telephone transmit/base station receive frequency of another standard (e.g., cellular), and converts transmissions by a base station or similar device (e.g., a base station simulator) from the telephone receive/base station transmit frequency of the one standard to the telephone receive/base station transmit frequency of the other standard. The two frequency conversions occur simultaneously on two parallel legs under the control of a PLL dual frequency synthesizer, which is in turn controlled by user input (in the case where the adapter is used to allow, e.g., PCS telephones to be tested on cellular test equipment) or by the base station (in the case where the adapter is used to allow, e.g., PCS telephones to be used with a cellular base station).

Abstract: A transceiver operable in both the cellular and PCS frequency bands which uses a single voltage controlled local oscillator in an intermediate frequency stage for both the cellular and PCS signals. The oscillator is operative for upconverting transmitter signals and downconverting receive signals for both cellular operation and PCS operation. A second voltage controlled local oscillator in a stage between the transceiver antenna and the intermediate frequency stage is operative for only PCS operation to upconvert PCS transmitter signals and to downconvert PCS receive signals. This is accomplished by the use of a switchable intermediate frequency local oscillator in the transmitter path of both the cellular and PCS signals.

Abstract: A cellular telecommunications device and method for achieving dual-mode cellular communications. The cellular telecommunication device comprises switchable loop filters, a loop filter switch controller, a programmable frequency synthesizer, and a voltage controlled oscillator arranged in a phase-locked loop configuration. The switchable loop filters comprise low-pass filters to optimize the performance of the device in both the analog and digital modes of cellular communications. Mode changes are facilitated by the switch controller which automatically configure the loop filters arrangement in response to a mode code sent to the cellular device from a cellular base station.

Abstract: A linear amplifier includes a feed forward circuit which is operative to eliminate distortion of the amplified signal by utilizing a second circuit path parallel to the amplification path to generate a distortion cancellation signal and combine it with the output of the amplification path to cancel the distortion. The gain and phase of the feed forward circuit is automatically adjusted by discrete steps through the operation of a stored program controller. The initial adjustment step is set at some minimum discrete value and its effect on the cancellation level of the feed forward circuit is evaluated. If the cancellation level does not change by a specified amount the adjustment step is increased by a discrete amount. Adjustment of the cancellation level is continued by discrete steps under control of the stored program control until a desired cancellation level is achieved. The number of step adjustments permitted is preset at some value.