NXP offers the AISG transceiver products as pre-programmed single modem or dual modem devices. The dual modem devices have 2 fully independent transceivers that can each be separately configured by the user to any desired setting. The pre-programmed modems can be used with their default parameter settings that are AISG compliant. Changing the modem settings (mainly receiver sensitivity and transmitter output power level) is possible by standard I2C bus access. The settings are stored in the internal non-volatile flash memory of the product and can be either programmed prior to assembling the device as part of the system, or in-system if I2C bus access is provided. The modem device can have 4 different I2C slave addresses, which allows connecting 4 devices to the same I2C bus, or when using a dual modem device, a total of 8 AISG transceivers on a single I2C bus. Therefore no hardware components need to be changed. The AISG transceivers can even be configured during site installation.
Embedded ARM Cortex M3 processor
In addition to the single and dual standalone AISG transceiver products, NXP also provides a version with an embedded 94 MHz ARM Cortex M3 processor. Also these come in a single and dual AISG transceiver version. The ARM processor includes a broad range of interfaces like PWM output, multi-channel ADC/DAC, and a high number of GPIO pins. This makes the ASC31xx AISG devices a flexible solution for tower mounted amplifiers, antennas with remote electrical tilt control, or adjustable filters and combiners. With 256 kbytes of integrated flash memory and 16 kbytes of SRAM there is sufficient memory for both the AISG protocol stack and application software.
Programmable transmitter output power
Our ASC301x and ASC31xx AISG transceiver devices with integrated 50 Ohm termination offer a transmit power to the feeder cable from 0 dBm to 10 dBm, or 5dB higher than the output power required by the AISG standard. This can be used to compensate for external circuit attenuation after the transmitter. Transmitter power is programmable in steps of 1 dBm for a transmitter output level up to 5 dBm, and in steps of 0.5 dBm for transmitter output levels of 5 to 10 dBm. The emission profile is AISG Compliant.
Programmable receiver ON-OFF threshold
The receiver band pass filter guarantees excellent performance even at low signal strengths in the presence of co-channels. The receiver provides 3 sensitivity modes for selecting ON-OFF thresholds. These 3 sensitivity modes are as follows: the standard AISG (default) sensitivity mode, the High sensitivity mode and the Ultra High sensitivity mode. In the Standard AISG sensitivity mode the ON and OFF thresholds are set to -12 dBm and -18 dBm as per the AISG standard. While in the highest sensitivity mode (Ultra High Sensitivity mode) the sensitivity is as high as -18 dBm. The higher sensitivity modes are available to compensate for attenuation due to external circuits in front of the receiver.
Support of extra 4.352 MHz and 6.528 MHz carrier frequency
In addition to the standard AISG carrier frequency of 2.176 MHz, all NXP AISG transceiver devices can be programmed by the user to operate also on 4.352 MHz or 6.528 MHz. This unique feature allows channel multiplexing over a single RF feeder cable by programming 2 transceivers to a different carrier. These 2 transceivers can either be 2 separate single modem NXP AISG transceiver products, or both part of the same dual modem NXP ASIG transceiver product, since the modems in the dual modem AISG transceiver products are fully independent.