This is one of the simplest FM transmitters that can be built. It does not require any tuning, and transmit frequency is crystal locked to 90MHz. It eliminates frequency drift common to LC-based FM transmitters. This design is best suited for broadcasting voice or music up to a distance of fifty metres depending on the antenna used.

The LTC3109 from Linear Technology is a highly integrated DC/DC converter specifically designed for energy harvesting applications. It can operate from ultra-low input voltages as low as 30mV, utilizing a unique, proprietary auto-polarity architecture to function regardless of input polarity. The component is ideal for harvesting energy from thermoelectric generators (TEGs) and thermopiles, efficiently converting this energy to power remote sensors, wireless transmitters, and low-power devices. Key features include selectable output voltages of 2.35V, 3.3V, 4.1V, or 5V, a 2.2V low-dropout (LDO) regulator, a logic-controlled output, and an energy storage system to maintain operation during power interruptions. The LTC3109 is encapsulated in a small, 20-lead (4mm × 4mm) QFN or SSOP package, making it compact and suitable for space-constrained applications in HVAC systems, building automation, and industrial wireless sensing. Additionally, the power good indicator and the ability to use compact step-up transformers further enhance its suitability for low power, energy-harvesting systems.

This is one of the simplest FM transmitters that can be built. It does not require any tuning, and transmit frequency is crystal locked to 90MHz. It eliminates frequency drift common to LC-based FM transmitters. This design is best suited for broadcasting voice or music up to a distance of fifty metres depending on the antenna used.

The Texas Instruments DAC3484 is a highly integrated, low-power, quad-channel, 16-bit digital-to-analog converter (DAC) capable of sample rates up to 1.25 GSPS. This component is designed to simplify complex transmit architectures in telecommunications and broadcast systems, offering features such as 2x to 16x digital interpolation filters with more than 90 dB of stop-band attenuation, which eases data interface and reconstruction filter design. Additionally, the DAC3484 includes independent complex mixers with fine and coarse mixing options for flexible carrier placement, a low jitter clock multiplying phase-locked loop (PLL) for simplified clocking, and digital Quadrature Modulator Correction (QMC) for IQ compensation in direct up-conversion applications. The 16-bit LVDS data bus, equipped with on-chip termination, a FIFO, data pattern checker, and parity test, along with multiple device synchronization capability, addresses the needs for high speed and precision in applications such as cellular base stations, diversity transmitters, and wideband communications. Offering options for very low power consumption and available in both 88-pin WQFN and 196-ball NFBGA packaging options, the DAC3484 is characterized for operation across the industrial temperature range of -40℃ to 85°C, making it a versatile choice for systems designers requiring high performance, multi-channel DAC solutions.