Equipment information

Dymar Electronics Limited 1785 Other
Dymar Electronics Limited
Model 1785
Category: Measurement instruments
Group Other
Description AM FM Modulation Meter
                                    The Dymar AM/FM Modulation Meter Type 1785 is an all
solid state instrument for the measurement of depth
of modulation or frequency deviation of transmitters.
It is operated either from A. C. Mains or from its own
rechargeable battery and as much is equally suitable as
a laboratory instrument or as a portable field servicing
The frequency range covered is the whole of the V.H.F.
band and extends into the U.H.F. band to include
the mobile band of 470 MHz.
The sensitivity over the whole of this range is better
than 2.5 mV in 50 ohm (-40 dm) which permits loose
coupling to the transmitter under test.

The instrument is specifically designed for measurement
of narrow deviation transmitters in todays mobile
and portable radiotelephones, the most sensitive
deviation being 3 kHz. The local oscillator has low
residual F. M. noise of typically 44 db below 3 kHz.
Auxiliary outputs are provided both at the Intermediate
Frequency (500 kHz) for viewing the modulation envelope
and at Audio Frequency for measurement of distortion.

These manuals are available for the above equipment:

Manual Type Service and User Manual Dymar-4084-Manual-Page-1-Picture
Pages 34
Size 1.37 Mbytes (1439991 Bytes)
Language english
Quality Scanned document, all readable.
Upload date
MD5 d5c697982ca35448db1a1d25258f4904
Downloads 143 since 21 January 2013

1.	General Description,	1

2.	Specification.	2

3.	Operation,	5

4.	Technical description.	9

5.	Alignment procedure.	13

6.	Component List.	       16

7.	Circuit Diagrams,	29

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