UM450
Lectrosonics
UM450
Lectrosonics UM450 Belt-Pack Lavalier Transmitter
The latest digital/analog hybrid technique is presented in a classic Lectrosonics wireless belt-pack transmitter. 24-bit digital audio is combined with optimized FM to create unprecedented audio quality and RF performance. The RF transmission is an aggressively optimized FM system with +/-75kHz wide deviation for a high signal to noise ratio.
The overall system delivers full bandwidth audio frequency response up to 20kHz and the operating range of the finest analog wireless systems. The innovative servo bias input on the standard 5-pin connector provides a programmable, regulated voltage to accommodate a wide variety of electret microphones.
It is no longer necessary to install resistive pads for some mics to prevent overload of the input stage, divide the bias voltage down for some low voltage mics, or reduce the limiter range at minimum gain settings. To simplify wiring connectors, a single configuration for all microphones is now available for the UM450 transmitter input, and an alternate wiring configuration works well with all 5-pin inputs on Lectrosonics transmitters.
Compatibility with earlier analog Lectrosonics receivers and even some receiver models from other manufacturers is provided by custom firmware emulations built into the DSP code. A simple procedure using the frequency and power switches selects the desired operating mode.
The overall system delivers full bandwidth audio frequency response up to 20kHz and the operating range of the finest analog wireless systems. The innovative servo bias input on the standard 5-pin connector provides a programmable, regulated voltage to accommodate a wide variety of electret microphones.
It is no longer necessary to install resistive pads for some mics to prevent overload of the input stage, divide the bias voltage down for some low voltage mics, or reduce the limiter range at minimum gain settings. To simplify wiring connectors, a single configuration for all microphones is now available for the UM450 transmitter input, and an alternate wiring configuration works well with all 5-pin inputs on Lectrosonics transmitters.
Compatibility with earlier analog Lectrosonics receivers and even some receiver models from other manufacturers is provided by custom firmware emulations built into the DSP code. A simple procedure using the frequency and power switches selects the desired operating mode.
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Manufacturer Specs
Frequency selection: 256 frequencies in 100kHz steps
RF Power output: 250 mW (nominal)
Pilot tone: 25 to 32 kHz; 5kHz deviation
Frequency stability: ± 0.002%
Deviation: ± 75 kHz (max)
Spurious radiation: 90 dB below carrier
Equivalent input noise: –120 dBV (A-weighted)
Input level: Nominal 2 mV to 300 mV, before limiting. Greater than 1V maximum, with limiting.
Input impedance:
Dynamic mic: 300 Ω
Electret lavaliere: Input is virtual ground with servo adjusted constant current bias
Line level: 2.7 k Ω
Input limiter: Dual envelope “soft” limiter; greater than 30 dB range
Gain control range: 43 dB; semi-log rotary control
Modulation indicators: Dual bicolor LEDs indicate modulation of -20, -10, 0 and +10 dB referenced to full modulation
Audio Performance (overall system)
Frequency Response: 32 Hz to 20 kHz (+/-1dB)
THD: 0.2% (typical)
SNR at receiver output*:
SmartNR No Limiting With Limiting
OFF 103.5 108.0
NORMAL 107.0 111.5
FULL 108.5 113.0
Input Dynamic Range: 125 dB (with full Tx limiting) Low frequency roll-off
Adjustment: –18 dB/octave; adjustable from 35Hz to 150Hz
Controls
• Two position “ON-OFF” power switch
• Audio input gain knob
• Low frequency roll-off pot on side panel
• Two 16-position rotary switches adjust frequency
Audio Input Jack: Switchcraft 5 pin locking (TA5F)
Antenna: Detachable, flexible wire supplied
50 Ω port allows connection to test equipment
Battery: Precision compartment auto-adjusts to accept any known 9 Volt battery
Battery Life
• Rechargeable Lithium Ion Polymer: 3.5 hours
• Alkaline dry cell at room temperature: 1.5 hours
• Lithium dry cell (not recommended)
• See FAQ 89 at: http://www.lectrosonics.com/faq.htm
Emission Designator: 180KF3E
*Note: the dual envelope “soft” limiter provides exceptionally good handling of transients using variable attack and release time constants. Gradual onset of limiting in the design begins below full modulation, which reduces the measured figure for SNR without limiting by 4.5 dB.
RF Power output: 250 mW (nominal)
Pilot tone: 25 to 32 kHz; 5kHz deviation
Frequency stability: ± 0.002%
Deviation: ± 75 kHz (max)
Spurious radiation: 90 dB below carrier
Equivalent input noise: –120 dBV (A-weighted)
Input level: Nominal 2 mV to 300 mV, before limiting. Greater than 1V maximum, with limiting.
Input impedance:
Dynamic mic: 300 Ω
Electret lavaliere: Input is virtual ground with servo adjusted constant current bias
Line level: 2.7 k Ω
Input limiter: Dual envelope “soft” limiter; greater than 30 dB range
Gain control range: 43 dB; semi-log rotary control
Modulation indicators: Dual bicolor LEDs indicate modulation of -20, -10, 0 and +10 dB referenced to full modulation
Audio Performance (overall system)
Frequency Response: 32 Hz to 20 kHz (+/-1dB)
THD: 0.2% (typical)
SNR at receiver output*:
SmartNR No Limiting With Limiting
OFF 103.5 108.0
NORMAL 107.0 111.5
FULL 108.5 113.0
Input Dynamic Range: 125 dB (with full Tx limiting) Low frequency roll-off
Adjustment: –18 dB/octave; adjustable from 35Hz to 150Hz
Controls
• Two position “ON-OFF” power switch
• Audio input gain knob
• Low frequency roll-off pot on side panel
• Two 16-position rotary switches adjust frequency
Audio Input Jack: Switchcraft 5 pin locking (TA5F)
Antenna: Detachable, flexible wire supplied
50 Ω port allows connection to test equipment
Battery: Precision compartment auto-adjusts to accept any known 9 Volt battery
Battery Life
• Rechargeable Lithium Ion Polymer: 3.5 hours
• Alkaline dry cell at room temperature: 1.5 hours
• Lithium dry cell (not recommended)
• See FAQ 89 at: http://www.lectrosonics.com/faq.htm
Emission Designator: 180KF3E
*Note: the dual envelope “soft” limiter provides exceptionally good handling of transients using variable attack and release time constants. Gradual onset of limiting in the design begins below full modulation, which reduces the measured figure for SNR without limiting by 4.5 dB.