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.
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 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.
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.
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 Receiver
PRC-2
WIRELESS
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
Memory
Controller
IFB R1a Receiver
Block Diagram
Control
Panel
LE
D
Compandor
Audio
Filter
Audio Out
IF Amp/F
M
Detector
5V
Regulator
9V
Battery
On/Off
Amp
Mixer
100n
100n
2p
Disc
RSSI
RF
Filter
RF
Amplifier
Frequency Synthesizer
PB Switch
Pwr On/Off
,
Audio Level.
Control
Knob
Pilot
Tone
Detector
Pilot
Tone
Mute
Cord
(Ant.)
Earphone
2.5vdc
2.5vdc
MAX
LEVEL
MONO PLUG (Open
)
STEREO PLUG (Closed)
S
T
R
Freq
Switches
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)
Specifications
Americas and Asia
4065 Hollis Street
Emeryville, CA 94608, USA
Tel: 1-510-496-6600
•
Fax: 1-510-496-6699
Wireless IFB Receiver
PRC-2
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.
IFB PRC-2 RECIEVER
BLOCK DIAGRAM
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
