4
Figure 1 - R1a Control Panel
LECTRO R1a
AUDIO
LEVEL
SCAN
(PUSH)
OFF
MAX
IFB RECEIVER
GENERAL TECHNICAL DESCRIPTION
The IFBR1 was upgraded to the IFBR1a by adding a number of important and useful features: (1) Two rotary HEX
switches to manually set the operating frequency, (2) Automatic sensing/control of a mono phone plug to eliminate the
mono/binaural switch, and (3) A multi-color LED for battery status. The Frequency scan and memory features were
retained.
The IFB R1a Receiver is comprised of a number of functional subsystems as shown in fig. 1, Control Panel and fig. 4,
Receiver Block Diagram.
GENERAL FEATURES
The frequency agile IFB R1a FM Receiver is designed to operate with the Lectrosonics IFB T1 Transmitter and features
microprocessor control of 256 frequencies of operation within each frequency block. Each block covers 25.5 MHz with
0.1 MHz frequency spacing. Any one of ten different frequency blocks are factory available from 512 MHz to 805.5
MHz (except 608 to 614 MHz).
The unique microcontroller design in this receiver provides simple one knob and one LED operation for audio level,
switching frequencies (channels), and easy on-the-fly programming. The receiver frequency can be set by manually
using the two rotary HEX switches on the side of the unit or by using the automatic scan and store function, or both.
When powered ON, the receiver will default to the frequency set by the switches. A nonvolatile memory can store up
to five additional frequencies accessible by pressing the knob. The memory remains during power OFF and even with
the battery removed.
The IFB R1a Receiver uses 20 kHz FM deviation for efficient use of the bandwidth and a single band compandor for
clean quiet audio.
The Pilot Tone squelch locks the reception to the mating IFB T1 Transmitter and ignores other signals.
The receiver operates on one 9 Volt alkaline battery for up to 8 hours and features a tricolor LED low battery indicator.
The voltages are internally regulated for stability.
The receiver is housed in a compact, rugged, lightweight aluminum enclosure. The unit features a durable removable
belt clip and an integral swing-aside battery compartment door.
CONTROL KNOB
(fig. 1)
The single front panel control knob performs multiple functions;
1.
Rotate for Power ON/OFF
3.
Push quick, Channel Switching
2.
Rotate for Audio Level
4.
Push and rotate for Scan and
Channel programming,
Refer to the RECEIVER OPERATING INSTRUCTIONS for full details on how
to use the single knob control for channel selection, scanning, and program-
ming of the five memory locations.
LED INDICATOR
(fig. 1)
The three color LED indicator on the front panel provides multiple functions.
CHANNEL NUMBER - The LED will blink OFF a number of times corresponding to the Channel Number when the unit
is switched ON and also when a new frequency is added to an open channel. For example, for channel 3 the LED
would blink OFF three times. After blinking the channel number the LED will return to a steady ON indicating normal
operation.
BATTERY STATUS
–
During normal operation, when the LED is GREEN, the battery is good. When the LED is YEL-
LOW the battery is getting low. When the LED is RED, the battery is nearly depleted and should be replaced.
PROGRAMMING FUNCTIONS - In the programming mode, the LED will blink at a fast rate to indicate scanning for an
active frequency. It also flashes briefly to indicate a frequency has been programmed into a channel.
