Wireless IFB (interruptible fold back) systems are used for talent cueing and crew communications in broadcast and motion picture production. In other cases, the IFB system is used by directors and other management to monitor program audio during a production. The IFBR1B receiver provides simplicity and flexibility in a package that is intuitive for untrained users to operate. In spite of its tiny size, the new IFBR1B receiver offers excellent performance on par with all of Lectrosonics' IFB products.

The design uses +/-20 kHz FM deviation for efficient use of the bandwidth, with compandor noise reduction circuitry for an excellent signal to noise ratio. A supersonic Pilot Tone signal controls the audio output squelch to keep the receiver silent when no transmitter signal is received. The incoming RF signal is filtered and amplified, then mixed down to the IF frequency with a microprocessor controlled synthesizer.

If a monaural earpiece is connected, this condition is automatically accommodated, with no loss of audio output power or battery life. Full output power is available with either type of connector, without the power losses that result from a resistive circuit design. The headphone cable doubles as the receiving antenna. The receiver will drive a wide variety of earbuds, headphones and induction neck loops at substantial levels, with loads from 16 Ohms to 600 Ohms.

An attached sliding door makes battery installation easy. The USB port is located in the battery compartment. The receiver operates on a single 3.6 V rechargeable LB50 Li-ion battery that will provide about eight hours of operation per charge. The LED indicator changes color from green to red as the battery voltage declines to