Model CVR-1500
1. Power On/Off switch
with switch guard
2. Signal strength, low battery
and frequency lock indicators
3. Active Antenna Indicator
lights
4. Channel selector switch
5. Audio output level control
1 2 3 4 5
DIVERSITY VIDEO-AUDIO RECEIVER
MODEL CVR-1500
6 7 8 9
6. Video output jack (BNC)
7. Barrier strip connector
for power and audio
8. Mini-DIN input connector
for power & audio
9. Three antenna input jacks (BNC)
• Greatly reduces the number of picture dropouts & breakups when Transmitter or Receiver is in motion.
• Virtually no loss of picture quality due to cars or people moving between the Transmitter and Receiver.
• TrueD™ diversity allows you to walk or drive around with one of our CVT series Transmitters and enjoy almost dropout free reception within the Transmitter's normal range.
• The five section signal strength indicators are a real help in evaluating location, antenna position and range.
The first three lights are green showing excellent to moderate signal strength. The next light
Is yellow, warning of a weak signal. The red light means that the signal is probably not usable.
• The red LED light also serves as a low battery warning by blinking when the battery falls to 10.5 volts.
• The Receiver performs a self-check when first turned on.
• When another channel is selected, a green light will blink to let you know that the internal phase lock circuitry is functioning properly and will stop blinking once it has achieved frequency lock.
• Two parallel power & audio connectors are provided -- a 4 terminal barrier strip & a 4 pin mini-DIN – use whichever is most convenient for your application.
• The Receiver may be attached to a wall or other surface using an optional slide-on bracket. It may be placed on a desk or mounted to an irregular surface with the hardware provided.
• 10 User selectable channels; up to 4 may be in operation in the same area.
• Changeable color-coded plastic side panels may be inserted to distinguish operating frequency used between multiple Transmitter and Receiver sets.
• No license required: US/ Canada approvals under FCC part 15 & IC RSS-210 (Canada).
• Works from a 12 or 24 Volt battery or AC Adaptor.
• An Audio level control is available to precisely match the CVR-1500’s audio output to your equipment.
How TrueD™ diversity works: Imagine dropping a pebble into a still pond. If the pebble is far enough away from the shore, the ripples continue away from the point of impact undisturbed. But what happens if we drop the same pebble near the shore? On the side facing away from the shore, the wavelets will be as before, undisturbed. If we look at the side facing the shore, what do we see?
If the shore is rocky, we may see that the waves are reflected back from the rocks into the incoming waves. If we look closely, we will see that the reflected waves combine with these incoming waves. Depending on their position relative to each other, they may combine and add to make a larger wave, or if the top of one wave and the bottom of another meet, they will even out leaving no sign of a wave at all.
This is what happens to radio waves as well. We have few reception problems when the Transmitter and Receiver are situated over flat land or water and the radio waves are undisturbed.
But in an urban environment, the radio waves are reflected from buildings, cars, light posts and metal objects in general, and may be absorbed by trees, shrubs and people. Inside a building, high frequency radio waves will be reflected by filing cabinets, metal studs in walls, lighting fixtures, metal desks, etc.
This is why when we try to use a cellular phone inside a building we may experience good reception only a foot or two from a problem area as the waves may combine and cancel in one area and add in another.

Now if we get tricky, we can place three antennas, several radio wavelengths apart, and look at the signal coming from each one.
Statistical studies show that almost 100% of the time, one of the three signals will be good as long as they are within range.
But we can't just combine the three signals and hope for the best, because they will have a random relationship with each other and we will have waves adding and canceling, just as when the wake from two passing boats cross. This is called antenna diversity, and it just doesn't work reliably. Instead, our Coherent CVR-1500 looks at the output of all three antennas and very quickly samples the signal strength of each one and looks at the quality of the Video as well. Our internal microcomputer decides which antenna has the best signal, and switches to it, giving you the best possible picture and sound. This happens so quickly that you will not even be aware of a possible problem before it is corrected. Three green lights on the front panel show which antenna has been selected.
Operating Distance: 1000 ft (305m) line of sight (US/ Canadian version). Much more or less depending on conditions, antennas used, elevation, etc. Government & Export version will have considerably more range.
Operating Frequency: 902-928 MHz in 10 User selectable channels. Up to 3 channels may be used in the same area simultaneously.
Export model is available to 1300 MHz, greatly increasing the number of available channels.
Receiver Type: FM, Single conversion superheterodyne with frequency control via synthesized phase locked loop, crystal referenced.
Front end noise figure
Frequency stability (-20ºC to +60ºC, -4ºF to +131ºF)
Video System:
<2.5 dB
0.003%
NTSC or PAL
Video level (internally adjustable) 1.0 Volt p-p into 75 Ohms
Ohms
Video bandwidth
Video signal to noise ratio referenced to:
1st green light
2nd green light
3rd green light
Yellow light
Red light
Differential Gain at -40 dBm RF input
Differential Phase at -40 dBm RF input
Audio Output (except with CVT-500)
Line output (Receiver) adjustable over:
Frequency Response at 20 dB below full deviation
Total harmonic distortion (before limiting)
Audio Modulation Type
Maximum deviation
System signal to noise ratio at ± 50 kHz deviation
Pre & deemphasis
Audio Carrier Offset from Video
Power
10 Hz to 3.0 MHz ± 1 dB; typical ± 1 dB 10Hz - 4.2MHz
10 Hz to 5.5 MHz +1, -3 dB
Received Signal Strength Indicator (RSSI)
RF level -40 dBm Video SNR 60 dB 64 dB typical
RF level -50 dBm Video SNR 55 dB 60 dB typical
RF level -60 dBm Video SNR 52 dB 55 dB typical
RF level -70 dBm Video SNR 45 dB 48 dB typical
RF level -80 dBm Video SNR 30 dB 34 dB typical
Usable picture to -87 dBm
<5 % (3% typ.)
<5 º (4° typ.)
All dB figures referenced to 0 dB = 0.774Vrms
0 dB to +10 dB at ± 50 kHz Deviation
30 Hz to 15 kHz +1, -3 dB, 60 Hz to 10 kHz ± 1 dB
(may be extended to -3 @ 30 kHz.)
0.5% at 400 Hz (0.25% typ.)
FM
± 50 kHz
65 dBA
75µ Second
6.5 MHz
12 VDC (10.5-16 V)
Current consumption
Mechanical
Size
With connectors & bracket
Weight
With connectors & bracket
Antenna connectors (3)
Video output connector
Power & audio output connector
320 mA at 12 VDC
5.7W x 6.2L x 1.2H in (145 x 157.5 x 30 mm)
5.7W x 7.9L x 1.4H in (145 x 201 x 36.8 mm)
18.3 oz (520 g)
22.9 oz (648 g)
50 Ohm BNC
75 Ohm BNC
4 pin mini-DIN & 4 terminal barrier strip in parallel
Environmental
Operating temperature
Storage temperature
Humidity range (non-condensing)
-20ºC to +60ºC (-4ºF to +131ºF)
-40ºC to +70ºC (-40ºF to + 158ºF)
5 to 90%
Approvals: FCC & Industry Canada No licensing required under FCC part 15.249 & IC RSS-210 for standard systems.
Specifications subject to change without notice.
28245 Avenue Crocker Suite 200 Valencia, California 91355 USA
PHONE (661) 295-0300 FAX (661) 295-0090 e-mail: info@cocom.com
Website: www.cocom.com
 1998 Coherent Communications, Inc.
Rev. 10/17/01
Printed in USA