The Harman Kardon Go + Play is a portable sound station that uses a pair of two-way 30-watt-RMS speakers each comprising a high-frequency transducer and high-excursion (25mm peak-to-peak travel) woofer. High-end Digital Signal Processors (DSPs) and a computer-optimised 360-degree soundstage deliver class-leading levels of audio detail and dynamics across a full 40Hz to 20kHz frequency-response range.
The JBL Radial entertainment dock delivers a 60-watt-RMS output across the same frequency range via two 15-watt midrange/high-frequency aluminum-domed Odyssey speaker drivers plus a single low-frequency 30-watt neodymium-magnet-based woofer.
The remote used with the Harman Kardon Go + Play also offers full navigation functionality for iPod, including the ability to browse by song, artist or album, and to select playlists, slideshows and videos. It was designed to handle 10 functions using only six buttons. RF remote controls, in comparison, use non-directional radio frequencies to communicate. This gives users the hugely convenient ability to control a device from an adjoining room.
The ultra-low power (ULP) yet high-performance characteristics of the nRF24L01 2.4GHz transceivers mean that they can typically run on coin cell power sources for periods of up to one year or more (depending on duty cycle), making them ideal for small-form-factor RF wireless connectivity without loss of functionality or operational reliability. One transceiver is used in the remote with a ‘paired’ device in the equipment to be controlled.
In operation, the nRF24L01 employs Gaussian Frequency Shift Keying (GFSK) modulation optimised for ULP wireless applications. When transmitting the nRF24L01’s supply current is 11 mA peak (at -0 dBm output power, sufficient for 30-ft/10m range). In receive mode, peak supply current is 12.5 mA. When not transmitting, the nRF24L01 enters an ultra-low power standby mode, consuming just 0.9 ìA. These extremely low power characteristics ensure excellent battery life even from coin cells. The nRF24L01 has a raw on-air data rate of up to 2 Mbps, providing plenty of overhead for the data transfer required for menu-browsing updates on a remote control with built-in screen.
It is supplied with a customised Frequency Agility Protocol (FAP) and can be optimised for either low latency (with an average response time of 2.5ms including RF power on and link up time) or low power with a latency of between 30 and 50ms. The FAP rapidly hops to a different frequency if communication is interrupted by other 2.4GHz sources, such as Bluetooth wireless technology or WiFi, to ensure a robust communication link.