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Frequency Agile UHF Belt-Pack Transmitter

Rio Rancho, NM – USA

A/D CONVERTER AND DSP PROCESSOR

The processed audio signal enters the A/D converter to generate a digital signal for the modulator.  A proprietary
algorithm is used for sampling and compression to minimize noise and distortion, and provide a wide, flat frequency
response.  The signal then enters the modulator to generate a digitally modulated radio signal.

OUTPUT SECTION

Intermodulation (IM) occurs in the final amplifier stages of conventional transmitters when the transmitters are within
a few feet of each other.  This can create serious problems in multi-channel wireless systems when an IM signal falls
on the carriers, IF frequencies, etc. of the systems being operated.  To eliminate this problem in the UM700, the
modulated radio signal passes through a circular isolator before entering the antenna.  The circular isolator functions
like a “one-way check valve” to allow the RF signal to pass through to the antenna, but not to pass backwards into
the amplifier stage.  RF signals from other nearby transmitters cannot reach the output amplifier in the UM700.  This
provides excellent stability and eliminates IM in the output stage of the transmitter.

LONG BATTERY LIFE

High efficiency circuits and switching power supplies throughout the design allow over 4.5 hours of operation using a
single 9 Volt alkaline battery.  (A 9V lithium battery will provide over 14 hours of operation.)  The battery compartment
is a unique mechanical design which automatically adjusts to fit any brand of battery.  The battery contacts are spring
loaded to prevent “rattle” as the unit is handled.

FREQUENCY AGILITY

700 Series wireless systems are available on eight different “blocks” of 256 frequencies, from 537.600 to 767.900
MHz.  Each of these blocks provides 256 selectable frequencies in 100 kHz steps over a 25.6 MHz bandwidth.  This
wide variety of selectable frequencies alleviates carrier interference problems in mobile or traveling applications.  Two
16-position rotary switches on the side panel of the unit are used to select the frequency.

The UM700 transmitter section uses a synthesized, frequency selectable main oscillator  The frequency is extremely
stable over a wide temperature range and over time.

ANTENNA

At UHF frequencies, where wavelengths and antennas are shorter than at VHF frequencies, a resonant length wire is
preferred over using the microphone cable as the antenna.  The antenna on the UM700 consists of a flexible 1/4
wavelength bronze cable, detachable via an SMA connector.  The impedance of this connector is 50 Ohms.

Содержание UM700

Страница 1: ...UM700 DIGITAL FREQUENCY AGILE UHF BELT PACK TRANSMITTER LECTROSONICS INC Rio Rancho NM www lectrosonics com OPERATING INSTRUCTIONS and trouble shooting guide...

Страница 2: ...SCRIPTION 4 CONTROLS AND FUNCTIONS 6 BATTERY INSTALLATION 8 OPERATING INSTRUCTIONS 8 OPERATING NOTES 9 ADJUSTING THE TRANSMITTER FREQUENCY 9 MICROPHONE CORD TERMINATION 10 5 PIN INPUT JACK WIRING 11 A...

Страница 3: ...ignal processing provides a superior limiter Eavesdropping is difficult and secure encryption techniques can be implemented The UM700 is a rugged machined aluminum package in a belt pack configuration...

Страница 4: ...orithm is used to contain the RF energy into a narrower bandwidth than other digital systems to allow the 700 Series system to utilize frequencies in FCC Part 74 for broadcast and motion picture produ...

Страница 5: ...e of the transmitter LONG BATTERY LIFE High efficiency circuits and switching power supplies throughout the design allow over 4 5 hours of operation using a single 9 Volt alkaline battery A 9V lithium...

Страница 6: ...y in the transmitter as follows Green battery good Yellow battery getting low Red battery very low change now Blinking Red battery critical failure imminent FREQUENCY ADJUST located under the sliding...

Страница 7: ...cording to the low frequency response of the mic capsule being used The low frequency roll off control is used to reduce the undesirable effects of very low frequency audio often pro duced by air cond...

Страница 8: ...the door open and take note of the polarity marked inside showing the location of the positive and negative terminals You can see the large and small contact holes inside the battery compartment with...

Страница 9: ...AUDIO LEVEL control so check this adjustment as each new person uses the system If several different people will be using the transmitter and there is not time to make the adjustment for each individu...

Страница 10: ...ng TA5F Connector Assembly Mic Cord Stripping Instructions Caution Do not allow the shield wire to touch any metal part of the connector shell The shield wire is the antenna on VHF models and poor ope...

Страница 11: ...c capsule or connector to block the RF from entering the electret capsule This modification is shown on the next page VHF transmitters use the shield of the microphone cord as the antenna The UM700 us...

Страница 12: ...for line level signals is Signal Hot to pin 5 Signal Gnd to pin 1 pin 4 jumped to pin 1 and pin 3 jumped to pin 1 This gives a 40dB attenuator that allows signal levels much higher than 3V to be appl...

Страница 13: ...OCK RANGE COLOR WHIP LENGTH 21 537 600 563 100 Brown 4 74 22 563 200 588 700 Red 4 48 23 588 800 614 300 Orange 4 24 24 614 400 639 900 Yellow 4 01 25 640 000 665 500 Green 3 81 26 665 600 691 100 Blu...

Страница 14: ...oo low 2 Receiver output is disconnected cable is defective or mis wired 3 Sound system or recorder input is turned down DISTORTED SOUND 1 Transmitter gain audio level is far too high Check mod level...

Страница 15: ...ge 43 dB semi log rotary control Modulation indicators Dual multi color LEDs indicate modulation level in 5 steps at 20 10 5 0 5 dB with green yellow and red indications Low frequency roll off adjustm...

Страница 16: ...is a charge for an exact quotation We will be happy to quote approximate charges by phone for out of warranty repairs RETURNING UNITS FOR REPAIR You will save yourself time and trouble if you will fo...

Страница 17: ...17 Frequency Agile UHF Belt Pack Transmitter Rio Rancho NM USA This page intentionally blank...

Страница 18: ...l at our option repair or replace any defective parts without charge for either parts or labor If we cannot correct the defect in your equipment we will replace it at no charge with a similar new item...

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