Lectrosonics UH190 User Manual

UH190

Plug-on Transmitter

OPERATING INSTRUCTIONS

and trouble-shooting guide

LECTROSONICS, INC.

Rio Rancho, NM

INTRODUCTION

Thank you for selecting the Lectrosonics UH190 belt-pack transmitter. The UH190
combines over 80 years of engineering experience with the very latest components,
in a design that addresses the most demanding professional applications.

The design of the UH190 was the direct result of numerous conversations with
users, staging and touring companies and dealers across the US. The specific
concerns and needs brought up in these conversations led directly to the develop­ment of the operational features offered on the UH190.

The UH190 is a rugged, machined aluminum package. 5 Volts of bias voltage is
available to power electret mics with either positive or negative bias. Level indicating
LEDs are provided to make level settings quick and accurate, without having to view
the receiver. The battery compartment accepts any 9 Volt alkaline battery and
makes a positive connection via self-adjusting contacts.

Only the UH190 transmitter is covered in this manual. Companion receivers are
covered in separate manuals. The UH190 will operate with any 190 Series Lec­trosonics receiver on the same frequency.

TABLE OF CONTENTS

INTRODUCTION .................................................................................................. 2

GENERAL TECHNICAL DESCRIPTION ............................................................ 3

CONTROLS AND FUNCTIONS .......................................................................... 4

OPERATING INSTRUCTIONS ............................................................................ 5

BATTERY REPLACEMENT ................................................................................. 6

TROUBLESHOOTING ......................................................................................... 7

SPECIFICATIONS AND FEATURES................................................................... 8

SERVICE AND REPAIR ....................................................................................... 9

RETURNING UNITS FOR REPAIR ..................................................................... 9

WARRANTY ......................................................................................... Back cover

The UH190 transmitter is FCC type accepted under Part 74: 470-608 MHz

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Plug-on Transmitter

GENERAL TECHNICAL DESCRIPTION

The UH190 transmitter is comprised of a number of functional subsystems as shown in the block diagram below.

The 190 system uses 15kHz deviation. The transmitter circuits are all regulated to allow full output power from the
beginning (9 Volts) to the end (7 Volts) of battery life. The oscillator crystal is shock mounted to provide ruggedness.
The input amplifier uses a Motorola 33078 op amp for ultra low noise operation. It is gain controlled with a wide
range input compressor which cleanly limits input signal peaks over 40dB above full modulation.

Traditionally, compandors have been a source of distortion in wireless microphone systems. The basic problem with
conventional systems is that the attack and decay times are always a compromise. If the time constants are fast,
high frequency transients will not be distorted, but this will cause low frequency distortion. If the time constants are
slower, low frequency audio distortion will be low, but high frequency transients will then be distorted. The 190
system introduces an entirely new approach to solving this basic problem, called “dual-band companding.”

There are actually two separate compandors in the 190 system, one for high frequencies and one for low frequen­cies. A crossover network separates the frequency bands at 1kHz with a 6dB per octave slope, followed by separate
high and low frequency compandors. The attack and release times in the high frequency compandor are fast enough
to keep high frequency transient distortion at a low level, and the low frequency compandor uses slower time con­stants, reducing low frequency distortion to well below that of a conventional compandor.

MIC

JACK

SHUNT

LIMITER

+5V BIAS
SUPPLY

INPUT
AMP

LIMIT

LED

SET
LED

AUDIO
LEVEL

FILTER

PEAK AUDIO

INDICATOR &

LIMITER
DRIVER

LP

COMPANDOR

Vref

BASS

TREBLE

LP FILTER

HP FILTER

COMPANDED

AUDIO

UH190 Block Diagram

Vreg

Vreg

XTAL OSC

+5VDC

+3.6VDC

X4

UHF TRANSMITTER

OFF

X2 X2 X2

ONMUTE

-9V

+9VDC

PWR
LED

Rio Rancho, NM – USA

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