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 intui- tive 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 circuit- ry 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 re- sult from a resistive circuit design. The headphone cable doubles as the receiving antenna.
The receiver will drive a wide variety of earbuds, head- phones and induction neck loops at substantial levels, with loads from 16 Ohms to 600 Ohms.