IEEE Consultants' Network of Long Island

DZIF: HOW IT RELATES TO ILOD-----Carl Schwab

The ZIF portion of DZIF refers to “Zero Intermediate Frequency” and it is just my favorite abbreviation for homodyne or synchrodyne. They all mean the same and are technologies that evolved in parallel with the superheterodyne around the 1920-1930 period. The  “D” part of DZIF refers to double conversion meaning that a high IF is used in addition to the ZIF.

In the hobby industry, the double conversion receiver had become standard and the usual design employed a 10.7 MHz FIRST IF and 455 KHz SECOND IF and the modulation most times was PPM FM. This design(S) evolved from about 1980 up to and beyond 2000. From a mechanical damage standpoint the 455 KHz transformers were the weak link. Also there were design missteps in gain distribution between the FIRST IF and the 455 KHz second IF.

Cell Phones and Passenger Aircraft - John Dunn, Consultant, Ambertec, P.E., P.C.

A power amplifier for CDMA service is described at http://www.maxim-ic.com/app-notes/index.mvp/id/456 where we read of performance that is characterized at an output power of +28 dBm, slightly more than 630.9 mW.

At http://www.datasheetcatalog.org/datasheet2/6/0esegl2hrtjs4ohlwyih6gc8p8ky.pdf , we find amplifier maximum output power specifications for W-CDMA service of +28.5 dBm which, slightly more than 707.9 mW.

At http://www.msnbc.msn.com/id/43456368/ns/business-us_business/t/new-elongated-boeing---debuts-paris/ , we read that Boeing has just introduced their new 747-8 jumbo jet. We also read that this aircraft will have 467 seats. The Airbus A380 can seat even more passengers, but let's just call this a jumbo jet seating capacity of 400+.