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This low power transceiver circuit project is designed using the ADF7242 fully integrated low-cost, short-range, low power transceiver designed for operation in the global 2.4 GHz ISM band.The receive path of the ADF7242 low power transceiver circuit is based on a zero-IF architecture enabling high blocking and selectivity performance. The transmit path is based on a direct closed loop VCO modulation scheme. The ADF7242 has a low consumption power that make it suitable for battery powered systems.

Low Power Transceiver Circuit diagram


The ADF7242 supports IEEE 802.15.4 compliant DSSS-OQPSK modulation with a bitrate of 250 kbps and also supports FSK and GFSK modulation with bitrates from 62.5 kbps to 2 Mbps.ADF7242 fully supports arbitrary data rates only for FSK mode of operation. The ADF7242 also has a built in battery monitor features that has a very low power consumption and may be used in parallel with any mode of operation, except SLEEP state. The battery monitor generates a battery alert interrupt for the MCU when the battery voltage drops below the programmed threshold voltage.

This 2 channels audio mixer is based on the 2n3904 transistors which forms 2 preamplifiers. The first preamplifier of the audio mixer has a high gain and can be used for microphone input, and the second one can be used to control the input of the audio level.

2 Channel Audio Mixer Circuit diagram


This two channel audio mixer require a power supply with the output voltage between 9 to 12 volts . For the audio signal you can use a CD player, mp3 player or other audio device and for the microphone you can use a normal dynamic microphone .