Z10042AV Construction and Operations Manual Page 5
General Information and Specifications
Description
The term “Norton Amplifiers” refers to a class of transformer feedback amplifiers developed by Dr.
David Norton and described in his US Patent No. 3,891,934, granted June 24, 1975 and now in the
public domain. (A copy of Dr. Norton’s patent is Appendix C to this Manual.) A Norton amplifier
permits the distortion reducing benefits of negative feedback to be applied without impairing the
amplifier’s noise figure. Hence, Norton amplifiers are also known as “noiseless feedback” amplifiers.
The Z10042AV is a broadband (25 KHz to 20 MHz) Norton-style amplifier providing 11 dB gain
(other gain values are possible) with very high 3rd order and 2nd order intermodulation intercepts,
IP3 and IP2, respectively, with a noise figure of approximately 2 dB. The Z10042AV is designed for
either indoor or outdoor use, with DC power supplied through either separate connections or
duplexed over the output coaxial cable. Optional indoor and outdoor die cast enclosures are
available for the Z10042AV.
The Z10042AV is derived from the Norton Amplifier developed by Dr. Dallas Lankford and
described in his publication Common Base Transformer Feedback Norton Amplifiers, dated 8 June
1994, revised 21 May 2007, available at
http://www.kongsfjord.no/dl/Amplifiers/Common%20Base%20Transformer%20Feedback%20N
orton%20Amplifiers.pdf.
The Z10042AV modifies Dr. Lankford’s design in several respects:
Automatic input disconnect upon DC power removal along with over-voltage gas trap
protection
Over voltage and reverse voltage protection on the DC Power.
DC power either separately or duplex power.
Optional balanced or unbalanced input.
Shunt fed to reduce effect of DC saturation of T2 and T4
Component values selected to extend lower -3 dB point to approximately 30 KHz.
Clifton Laboratories also offers the Z1203A DC power injector usable with the Z10042AV to provide
DC power over the output coaxial cable. This is useful for remote mounted amplifiers.
The Z10042AV is available as a kit, including a double sided, silk screened solder masked printed
circuit boards and all electronic parts or as an assembled and tested printed circuit board. Options
include an indoor enclosure with BNC connectors or an outdoor weatherproof die cast enclosure
with a choice of BNC, UHF or Type N connectors.
Typical kit construction time is three to five hours depending on your work practices. The kit is
suitable for relatively inexperienced builders, although Clifton Laboratories does not recommend it
to purchasers who have never built an electronic kit before. Also, if you have never wound a toroid
inductor or transformer, you might wish to ask an experienced builder to show you how it’s done.
