INSTRUCTION MANUAL T4 Multi-Frequency IFB Transmitter Featuring Digital Hybrid Wireless™ Technology Fill in for your records: Serial Number: Purchase Date: Rio Rancho, NM, USA www.lectrosonics.
T4 2 LECTROSONICS, INC.
Multi-Frequency IFB Transmitter Table of Contents Introduction.............................................................................................................................................................................................4 General Technical Description ..............................................................................................................................................................5 Audio Input Interface ..............................................
T4 General Technical Description The T4 IFB Transmitter is comprised of a number of functional subsystems, including Audio Input Interface, DSP Audio Processor and Pilot Tone, Frequency Synthesizer, Microcontroller, Transmitter, Antenna System and Power Supply. (See block diagram.) The T4 is designed to operate primarily with the Lectrosonics R1 and R1A IFB receivers, and is also capabable of operating with the Lectrosonics 100 Series, 200 Series, 400 Series receivers.
Multi-Frequency IFB Transmitter Pilot Tone The T4/R1A system uses an ultrasonic tone modulation of the carrier to operate the receiver squelch. This “pilot tone” consists of a 29.997 kHz signal in the DSP and is mixed with the audio signal to the FM modulator. The pilot tone controls the audio output muting of the receiver and is filtered out of the audio signal immediately after the detector in the receiver so that it does not influence the compandor or various gain stages.
T4 Front Panel Controls and Functions T4 Front Panel icon to indicate transmit (XMIT) mode. The MENU button is then used to navigate to the other function windows, see page..7? indicates the channel (or operating) frequency of the unit to the nearest 0.1 MHz (100 kHz). The LED display also indicates low input power by blinking continuously when the input voltage drops below 11.0 Volts. Select Buttons (Up and Down) OFF/TUNE/XMIT Switch OFF Turns the unit off.
Multi-Frequency IFB Transmitter T4 Menu Diagram Rio Rancho, NM 7
T4 Rear Panel Controls and Functions T4 Rear Panel 12 VDC (Power Input Connector) The T4 is designed to be used with the CH20 external (or equivalent) power source, which is plugged into the 6-18 VDC external power input connector. The nominal voltage to operate the unit is 12 VDC; although it will operate at voltages as low as 6 VDC and as high as 18 VDC. A suitable alternate power source must be able to handle 200 mA continuous consumption.
Multi-Frequency IFB Transmitter Installation and Operation 1) The T4 transmitter is shipped with pin 1 of the XLR input connector tied directly to ground. If a floating input is desired, a Ground Lift Jumper is provided. This jumper is located inside the unit on the PC board near the rear panel XLR jack. If a floating connection is desired, open the unit and move the Ground Lift Jumper to the desired location. 5) Attach the antenna (or antenna cable) to the BNC connector on the rear panel.
T4 Operating Notes The AUDIO LEVEL control should not be used to control the volume of the associated receiver. This gain adjustment is used to match the T4 input level to the incoming signal from the sound source to provide full modulation and maximum dynamic range. If the audio level is too high — the audio metering will exceed the 0dB level too frequently. This condition may reduce the dynamic range of the audio signal.
Multi-Frequency IFB Transmitter Troubleshooting Symptom: Possible Cause: Display Dead 1) External power supply disconnected or inadequate. 2) The External DC power input is protected by an auto-reset polyfuse. Disconnect power and wait about 10 seconds for the fuse to reset. No Transmitter Modulation 1) AUDIO LEVEL turned all the way down. 2) Sound source off or malfunctioning. 3) Input cable damaged or mis-wired. No Received Signal 1) Transmitter not turned on.
T4 Frequency Blocks and Ranges The table below lists the factory designated frequency ranges available for the T4 IFB Transmitter. Each T4 transmitter is built to cover a pre-selected range of frequencies (a “block”) as shown below. The transmitter will tune to any of 256 different frequencies within this factory assigned block. The block number is determined by this formula: 25.6 × Freq. (MHz) = Lowest freq. (MHz) in the block To determine a block number from a frequency: Freq. (MHz) divided by 25.
Multi-Frequency IFB Transmitter Specifications Operating Frequencies (MHz): Frequencies (Channels per block): Channel Spacing: Spurious & Harmonic Suppression: Frequency Stability: Temperature Stability: Channel Selection: Compatibility Modes (6) Pilot Tone: Modulation: Audio Response: Audio Compressor: RF Power Output: Output Impedance: Audio Input Levels: Audio Input Config: Audio Input Impedance: Gain Control Range: Audio Input Jack: Input Power: Power Input Jack: Indicators: Front panel controls: Rea
T4 Service and Repair If your system malfunctions, you should attempt to correct or isolate the trouble before concluding that the equipment needs repair. Make sure you have followed the setup procedure and operating instructions. Check the interconnecting cables and then go through the Troubleshooting section in this manual. We strongly recommend that you do not try to repair the equipment yourself and do not have the local repair shop attempt anything other than the simplest repair.
Multi-Frequency IFB Transmitter Rio Rancho, NM 15
LIMITED ONE YEAR WARRANTY The equipment is warranted for one year from date of purchase against defects in materials or workmanship provided it was purchased from an authorized dealer. This warranty does not cover equipment which has been abused or damaged by careless handling or shipping. This warranty does not apply to used or demonstrator equipment. Should any defect develop, Lectrosonics, Inc. will, at our option, repair or replace any defective parts without charge for either parts or labor.
