INSTRUCTION MANUAL DCHT Digital Transmitter Fill in for your records: Serial Number: Purchase Date: Rio Rancho, NM, USA www.lectrosonics.com DCHT Table of Contents Introduction Introduction ............................................................................ 2 The DCHT transmitter is designed to work with a com- DSP-controlled Input Limiter ................................................ 2 panion receiver (such as the Lectrosonics M2R, part DCHT Block Diagram ........................................................... 3 of the Duet IEM system) as an audio relay between an Features and Functions ........................................................ 4 audio production bag or cart and a camera or other au- Optional Battery Eliminator .................................................. 4 dio device. The 6-pin input jack accepts two mic or line Whip Antennas ..................................................................... 4 Battery Status LED Indicator ............................................... 5 level analog signals or AES digital signals from external Belt Clips .............................................................................. 5 sources with a variety of adapter cables. Analog in- IR (infrared) Port .................................................................. 5 puts can be linked for the same gain when used with a Status LED ........................................................................... 5 stereo source, or operate independently with individual Battery Installation ................................................................ 5 settings. Powering On and Off ............................................................. 6 Powering On in Operating Mode .......................................... 6 This third generation digital design features specially Powering On in Standby Mode ............................................ 6 developed, high efficiency digital circuitry for extended Powering Off ........................................................................ 6 operating time on two AA batteries. The transmitter can Power Button Menu ............................................................... 6 tune in coarse or fine steps across the UHF television Entering the Power Menu ..................................................... 6 band from 470.100 to 607.950 MHz, with a selectable LCD Menu Map ....................................................................... 7 output power of 10, 25 or 50 mW. Main Menu and Setup Screen Details .................................. 8 Entering the Main Menu ....................................................... 8 Studio quality audio performance is assured by high Main Window Indicators ...................................................... 8 quality components in the preamp, wide range input Connecting the Signal Source ............................................. 8 gain adjustment and DSP-controlled limiting. and Adjusting the Input Gain for Analog Inputs .......................... 8 settings are included for any lavaliere microphone, Selecting Frequency ............................................................ 9 dynamic microphones and line level inputs. Input gain Selecting M2R Receiver Functions ...................................... 9 is adjustable over a 51 dB range in 1 dB steps to allow Selecting Programmable Switch Functions.......................... 10 a precise match to the input signal level, to maximize Selecting the Low Frequency Roll-off .................................. 10 dynamic range and signal to noise ratio. Selecting StMode (stereo mode) ......................................... 10 Selecting Input Type ............................................................. 10 A separate switch is provided on the top panel that can Selecting Input Configuration ............................................... 10 be configured as mute, power or bypass. Selecting Battery Type ......................................................... 11 The housing is constructed of solid machined aluminum BatTime ................................................................................ 11 Enable/Disable Remote Control Function ............................ 11 for lasting ruggedness. The exterior is finished with an Setting Transmitter Output Power ........................................ 11 ultra hard, dark electroless nickel finish calledebENi . Locking/Unlocking Changes to Settings............................... 11 Firmware updates are made through a side panel micro Restoring Default Settings ................................................... 11 USB port. Input Connections ................................................................ 12 Microphone Cable Termination for Non-Lectrosonics Microphones .............................. 13 DSP-controlled Input Limiter Wireless Designer Software ................................................ 14 The transmitter employs a DSP-controlled analog audio Firmware Update Instructions .............................................. 14 limiter prior to the analog-to-digital converter. The limiter Specifications ........................................................................ 14 has a range greater than 30 dB for excellent overload Accessories ........................................................................... 16 protection. A dual release envelope makes the limiter Troubleshooting ..................................................................... 17 acoustically transparent while maintaining low distor- Service and Repair ................................................................ 18 Returning Units for Repair ................................................... 18 tion. It can be thought of as two limiters in series, con- nected as a fast attack and release limiter followed by a slow attack and release limiter. The limiter recovers quickly from brief transients, so that its action is hidden from the listener, but recovers slowly from sustained high levels to keep audio distortion low and preserve short term dynamic changes in the audio level. Canada ISED Notice This device operates on a no-protection, no-interference basis. Should the user seek to obtain protection from other radio services operating in the same TV bands, a radio licence is required. For further details, consult Innovation, Science and Economic Development Canada’s document Client Procedures Circular CPC-2-1-28, Voluntary Licensing of Licence-Exempt_Low-Power Radio Apparatus in the TV bands. 2 LECTROSONICS, INC. Digital Transmitter DCHT Block Diagram Input Jack 123456 CHANNEL 1 CHANNEL 2 (analog/digital selectable) Servo Bias Bias Voltage Servo Bias Bias Voltage Supply 0, 2 or 3.6V Supply 0, 2 or 3.6V A-D A-D Converter Converter HI/Lo Input Audio Input HI/Lo Audio Pass Preamp Preamp Pass Filter Filter Gain Rate I2S Gain I2S Adj Converter Adj Shunt Limiter Control Shunt Limiter Limiter Limiter Control D-A Converter I + Q Low Baseband pass Signals lters I2S (2) AA Batteries Switching Power Supply Power k Microprocessor LED Tricolor DSP Cloc Status Ready IR Port Firmware Update USB UART Jack Keypad IQ Modulator Oscillator PLL Ref Voltage Controlled Low Buer Phase Locked Loop VCTCXO Oscillator Pass Filters Filter 36.864 MHz Final Control Amplier Rio Rancho, NM 3 DCHT Features and Functions Status Ready LED Battery status LED Menu navigation Enter menu/Select item USB Port Return to previous screen Power/Power Menu access Programmable Bi-directional IR port function switch Whip Antennas Because the transmitter tunes across such a broad frequency range, it is best to use the ap- propriate antenna for maximum operation. Two antennas are included with the transmitter, and are shipped from the factory pre-cut and fully assembled. Each antenna covers three blocks. Audio Modulation Antenna Refer to the chart below to determine which an- input indicators* port tenna matches the operating frequency you will jack be using. Frequency Cap Block Range MHz Color Antenna Optional Battery Eliminator 470 470.100 - 495.600 Black AMM19 The transmitter can be powered by external DC using 19 486.400 - 511.900 Black AMM19 the optional LTBATELIM power supply adapter. The battery door is replaced by the adapter with a simple 20 512.000 - 537.500 Black AMM19 procedure. The adapter provides a locking coaxial con- 21 537.600 - 563.100 Red AMM22 nector and a variety of power cords and connectors are 22 563.200 - 588.700 Red AMM22 available. 23 588.800 - 607.950 Red AMM22 4 LECTROSONICS, INC. Digital Transmitter Battery Status LED Indicator Battery Installation The Power/Function LED on the top panel will mirror the keypad LED unless the programmable switch is set The transmitter is powered by two AA batteries. Lithium to Mute, and the switch is turned on. batteries are recommended for longest life. Alkaline, lithium or rechargeable batteries can be used The battery status circuitry compensates for the differ- to power the transmitter. The type of batteries in use are ence in voltage drop between alkaline and lithium bat- selectable in a menu on the LCD. teries across their usable life, so it’s important to select the correct battery type in the menu. When alkaline or lithium batteries are being used, the LED labeled BATT on the keypad glows green when the batteries are good. The color changes to red at a mid- point of the runtime. When the LED begins to blink red, there will be only a few minutes of operation remaining. The exact point at which the LEDs turn red will vary with battery brand and condition, temperature and power