An antenna diversity receiver is disclosed. A tank holds panels to collect light and water to guide light to the focus. The MCU can provide support for legacy endpoints as well. An image caching system may be implemented in the computer annotation systems to reduce image processing time. Sample rate estimating circuitry computes a difference signal representative of a time at which a data sample of the audio input signal is received and a time at which a corresponding audio output sample is required, and address generation circuitry generates the read and write addresses. The cartridge has a rigid plate having a first surface and a second opposing surface, with the plate having a meandering path provided therein.