Frequency Band A1: 470.100 - 537.575 MHz (Blocks 470, 19, and 20)
The design of the SMDWB transmitter delivers the advanced technology and features of Digital Hybrid Wireless® in a Lectrosonics belt-pack transmitter at a modest cost. Digital Hybrid Wireless® combines a 24-bit digital audio chain with an analog FM radio link to eliminate a compandor and its artifacts, yet preserve the extended operating range and noise rejection of the finest analog wireless systems. DSP “compatibility modes” allow the transmitter to also be used with a variety of analog receivers by emulating the compandors found in earlier Lectrosonics analog wireless and IFB receivers, and certain receivers from other manufacturers (contact the factory for details).
The housing is a rugged, machined aluminum package. The input jack is a standard Lectrosonics 5-pin type for use with electret lavaliere mics, dynamic mics, musical instrument pickups and line level signals. The LEDs on the keypad allow quick and accurate level settings without having to view the receiver. The unit is powered by two AA batteries. The antenna port uses a standard 50 ohm SMA connector. RF power for the SMWB & SMDWB models is selectable at 100, 50, or 25 mW (North American version) and 50 or 25 mW (certain export markets).
The switching power supplies in the provide constant voltages to the transmitter circuits from the beginning to the end of battery life, with output power remaining constant over the life of the battery. The input amplifier uses an ultra low noise op amp. Input gain is adjustable over a 44 dB range, with a DSP-controlled dual envelope input limiter providing a clean 30 dB range to prevent overload from signal peaks.
The SMDWB has a built in recording function for use in situations where RF may not be possible or to work as a stand alone recorder. The record function and transmit functions are exclusive of each other - you cannot record AND transmit at the same time. The recorder samples at 44.1kHz rate with a 24 bit sample depth (the rate was selected due to the required 44.1kHz rate used for the digital hybrid algorithm). The micro SDHC card also offers easy firmware update capabilities without the need for a USB cable or driver issues.