Europe, Middle East and Africa
7400 Beach Drive, Cambridge Research Park
Cambridge CB5 9TP, UK
Tel: +44 (0) 1223 815000 • Fax: +44 (0) 1223 815099 www.clearcom.com
Wireless IFB Receiver
PRC-2
Features:
• Preset (default) frequency can be set without power or transmitter signal
• Scan mode stores up to five additional frequencies
• Multi-color LED and rotary control for programming and operation
• High sensitivity for extended operating range indoors or outdoors
• Rugged machined aluminum housing
• Spring-loaded belt clip
• Attached battery door
• 8 hours battery life (alkaline)
• 20 hours battery life (lithium)
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 IFB PRC-2 receiver provides simplicity and flexibility in a package that is intuitive for untrained users to operate.
The default frequency of the receiver is set by two rotary switches on the side panel. Up to five additional frequencies can also be programmed into the receiver memory using the scan mode. If more than one frequency is stored in the receiver, the operator can scroll through all stored frequencies by simply pressing the volume knob.
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 lock the reception onto the matching transmitter and reject other radio signals.
Basic operation is simply a matter of rotating the knob to turn power on and adjusting the volume level. Additional frequencies are added by holding the knob in until the LED begins blinking and the receiver begins to scan. The receiver will search for signals that contain a pilot tone and automatically stop scanning and wait for the operator to either store that frequency or continue scanning.
The scanning process is performed at two different sensitivity levels. The first scan is performed at a reduced sensitivity to avoid falsely locking onto IM (intermodulation) signals rather than true carriers. This reduced sensitivity scan is necessary when the unit is programmed in close proximity to the transmitter. If no signals are found in the first scan, a single button push will set the receiver to full sensitivity and begin a second scan. Full sensitivity scanning is necessary to program the receiver at a distance away from the transmitter.
The receiver operates on a single 9 volt alkaline or lithium battery.
Alkaline battery life is up to 8 hours. Lithium battery life is well over
20 hours. The LED indicator changes color from green, to yellow, to red as the battery voltage declines to provide plenty of warning before operation ceases.
An internal relay in the receiver will automatically detect a monaural plug connected to the output jack and switch accordingly. Full output power is available with either type of connector, without the power losses that result from a resistive circuit design. The antenna input is provided by the shield of the cable and headset or earphone connected to the output jack.
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.
A special button push sequence is required to set the receiver into the scanning mode to prevent accidental changes to the receiver memory. Simplified instructions are laser engraved into the housing of the receiver.
The receiver is housed in a rugged machined aluminum package. A spring-loaded belt clip provides a secure mounting on a wide variety of belts, pockets and fabrics. The belt clip is removable to reduce its size and allow mounting into other types of bags and belt worn mounting systems common in field production.
Wireless IFB Receiver
Specifications
Operating Frequencies:
537.600 to 767.900 MHz (608 to 614 MHz not avail in USA)
Frequency control:
Crystal Controlled PLL Sensitivity: 1 uv
(20 dB SINAD)
Signal/Noise ratio:
95 dB A-weighted
Squelch quieting:
90 dB
AM rejection:
50 dB, 10 uV to 100 mV Modulation acceptance: ±20 kHz
Spurious rejection:
Greater than 70 dB
Third order intercept:
0 dBm
Frequency response:
100 Hz to 10 kHz, (±1db)
Pilot tone:
29.997 kHz, 4.5 kHz deviation (fixed crystal controlled)
Audio output:
1V RMS into 50 Ohms minimum
Antenna:
Headphone cable
Programmable memory:
Switches set default frequency; up to five additional frequencies can be stored in memory
Front panel controls:
Single knob controls Audio Output
Level, Power on, programming and Scan
Frequency Selection
Indicators:
Multi-color LED indicator for power on and battery status. Blinks to indicate channel number and during scanning.
Power requirement:
9V alkaline battery lasts about 8 hours
9V lithium battery lasts about 20 hours
Power consumption: 60 mA Weight: 7.3 oz with battery Size: 3.6 x 2.4 x 0.8 inches
(housing only) (belt clip and knob extend beyond the housing)
Power consumption:
60 mA
Weight:
7.3 oz with battery
Size:
3.6 x 2.4 x 0.8 inches (housing only) (belt clip and knob extend beyond the housing)
RF
Filter
Freq
Switches
Memory
Control
Panel
LED
RF
Amplifier
Frequency Synthesizer
Controller
Mixer
Disc
RSSI
IF Amp/FM
Detector
Pilot
Tone
Detector
Audio
Filter
PRC-2
Compandor
Pilot
Tone
Mute
Knob
PB Switch
Pwr On/Off,
Audio Level.
Control
2.5vdc
100n
2p
Amp
2.5vdc
100n
MAX
LEVEL
9V
Battery
5V
Regulator
On/Off
Audio Out
S
Earphone
T
R
Cord
(Ant.)
MONO PLUG (Open)
STEREO PLUG (Closed)
IFB PRC-2 RECIEVER
BLOCK DIAGRAM
The incoming RF signal is filtered and amplified, then mixed down to the IF frequency with a microprocessor controlled synthesizer. A pilot tone squelch system is used to keep the receiver silent when no carrier is present. The pilot tone signal is on a different frequency than Lectrosonics UHF wireless microphone systems to prevent interference when the systems are used in the same location.
The audio signal processing includes compandor noise reduction for low noise and excellent intelligibility. The receiver is housed in a compact machined aluminum enclosure. The unit features a durable removable belt clip and an integral rotating battery door that remains attached to the housing when opened. All nomenclature is laser engraved into the housing and the side panel to withstand physical abrasion and heavy use. A condensed instruction set is also laser etched into the side panel of the receiver.
Americas and Asia
4065 Hollis Street
Emeryville, CA 94608, USA
Tel: 1-510-496-6600 • Fax: 1-510-496-6699
Europe, Middle East and Africa
7400 Beach Drive, Cambridge Research Park
Cambridge CB5 9TP, UK
Tel: +44 (0) 1223 815000 • Fax: +44 (0) 1223 815099 www.clearcom.com
