      This file has descriptions of files contained in PUFF23_B.ZIP.

1) DESCRIPT  This file!

2) #README2  Lists main changes in PUFF 2.3, (from PUFF 2.0) and how some of
   the changes work. It also has a note on device (.DEV) files.

3) All device files in this zip file have S parameters referenced to
   a 50 ohm Zo. Device files can have a .DEV extension (there are 23 of these)
   or can be EEsof format with extensions of S1P, S2P, S4P etc. BFG135D.S2P
   is an example of a EEsof file. PUFF can also read S parameters contained in
   a .PUF circuit file. A device file can be made by copying S parameters from
   a data book to an ASCII text file, or may be obtained from transistor data,
   or other RF device data, downloaded from the internet. The data lines
   should have the same format as in a .PUF circuit file.

   Device files usually have comment lines stating what the device is.
   ERA1, ERA2, ERA, MAR-4, MAR-6, MAR-7, MAR-8 are monolithic microwave
   amplifiers made by Mini Circuits. MGA87653 in an amplifier made by HP.
   Four of the device files are for High Electron Mobility Transistors or
   HEMTs. MRF966.DEV is for a Motorola GAs FET. Files starting with BFG are
   for Philips bi-polar transistors. The other device files are for ideal
   parts without any frequency specification.

4) The three .COM files are TSR programmes that may be needed to print out
   an artwork from a .PUF circuit file. The HPG2COM.EXE file is for dumping
   an .HPG file to a plotter connected to com port COM1. HPG2COM.PAS is the
   source code.

5) The .PUF circuit files give some idea of the capabilities and versatility
   of PUFF.  N.B. All these files have had the artwork output option set to 2.
   This is for making an .HPG file.

a) 10THZ.PUF  This file has a single 50 ohm microstrip line in "Manhattan"
   format, with fd, the design frequency set to 1 THz (or 1000 GHz). This is
   the file I used for the extremely high loss test. PUFF 2.0 crashed when
   the plot got to 6.4 THz. PUFF 2.3 can plot to -500 dB, PUFF 2.0 goes to
   -370 dB.

b) 150M-LPF.PUF  This is a seven pole Chebyshev low pass filter designed for
   a return loss of 26 dB in the pass band and a cut off frequency of 150 MHz.

c) AMP.PUF  Is an amplifier with a narrow band L match at the input. It uses
   a FHX04 HEMT from device file FHX04.DEV (One of the .PUF files that came
   with PUFF 2.0).

d) BPF.PUF  This file demonstrates the use of coupled lines to make a band
   pass filter. Due to the high frequency and high dielectric constant of
   the board material, there are strong dispersion effects evident when a
   ! is added to parts specification. (Another file that came with PUFF 2.0).

e) BPF-1GHZ.PUF  This is the same circuit as BPF.PUF except fd is 1 GHz.
   The line lengths have also been set to the length of a single 50 ohm
   microstrip line. There is little difference in the plot when a ! is
   added to the parts line. The lower circuit differs only by the line length
   being 90 degrees. Cline width and spacing are calculated at fd=0Hz.
   Dispersion effects in microstrip increase the electrical length.

f) BALUNS.PUF  This file shows the difference in bandwidth of a 4:1 balun
   when the 180 degree section has the optimum Zo. A 4:1 balun using a
   transformer is included for comparison; the ratio is set to 1.001 so that
   the return loss plot is on the graph.

g) BFG135AM.PUF  This is a PUFF model of an amplifier that I've designed and
   built. Measured performance and PUFF predictions hardly differ. This amp
   was designed for use in a 2 metre repeater. Collector current is set to
   93 mA and is controlled with an active bias circuit; the emitter pins
   are directly grounded. Noise figure is 2.2 dB between 144 and 148 MHz and
   third order output intercept point is +37 dBm. Device files BFG135.DEV and
   BFG135D.S2P give the same plot results.

h) BGF135-D.PUF  This file shows how .PUF circuit files can be used as device
   files to build up complex circuits. PUFF assumes any unspecified S parameter
   to be zero. So the S22 and S12 plots are <-200 dB in this circuit because
   these parameters weren't plotted in 150M-LPF. The plot frequency range is
   limited to the range in BFG135AM.
   N.B. All device files used in the one circuit MUST have the same frequency
   unit e.g. MHz, and the same design Zo. Zo will generally be 50 ohms.

g) CHEBYLC.PUF  This is a Chebyshev bandpass filter with parts specified
   in terms of normalised Zo and admittance. (This file came with PUFF 2.0).

h) CUPLER70.PUF  Is a stripline directional coupler with a 20 dB coupling
   factor. To obtain a good directivity there must be a uniform dielectric
   constant in the space surrounding the coupled lines. Stripline satisfies
   this requirement. Changing the circuit to microstrip reduces directivity
   from 54.7 dB to 7.1 dB. I've made directional couplers using dimensions
   from PUFF that performed just the way PUFF predicted.

i) DIPLEXER.PUF  This is a diplexing filter that has a good match at the
   common port (1) whatever the input frequency. This filter could be used
   to diplex two antennas of different frequency to the one transmission line.

j) ELIP-LPF.PUF  This file shows that PUFF can be used at audio frequencies
   and with a design Zo other than 50 ohms. The each 33 mH coil has a
   parallel capacitor specified in the parts list with the Alt+P parallel
   sign. This is an elliptical low pass filter.

k) LPF-ARRL.PUF  Two low pass filter designs from the 2001 ARRL Handbook.
   The top circuit uses transmission line parts, the bottom one uses lumped
   parts. The Handbook said the design frequency was 720 MHz for both filters.

l) MINI-AMP.PUF  Two amplifier circuits using Mini Circuits MMICs. The input
   and output coupling capacitors have the self inductance modelled in. The
   resistors on the output side are the DC feed resistors from a 12 volt
   supply. These are shown as grounded in the circuit because a bypass
   capacitor at the 12 volt end grounds the resistors at RF.

m) RTS*.PUF  These files model the hybrid loop filters used in the VK2RTS
   repeater. Parts b and d simulate a co-axial quarter wave resonator of
   100 mm diameter. (The real resonator has a coupling loop instead of a
   tapped line.)  Parts g are pieces of RG213 co-axial cable which make up
   the hybrid loop. The RCL circuit is adjusted to produce an impedance
   equal to the impedance of the off-tune resonator at the notch frequency,
   to give phase cancellation at the output.

n) SWEEP-L.PUF  This just demonstrates a lumped component sweep.

o) WILKS-2M.PUF  This is a Wilkinson splitter circuit using lumped components.
   Port 1 is the input, ports 3 and 4 are the output. Power applied to port 1
   is split equally between ports 3 and 4.  There is good isolation between
   ports 3 and 4.

p) PROTO_7P.PUF  Is a seven pole Chebyshev lowpass filter using one ohm and
   one radian per second prototype component values from my filter programme.
   This file demonstrates the versatility of PUFF.

   R.G.Davison
