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-rw-r--r--octave/rf_bpf.m37
-rw-r--r--octave/rf_design.m77
-rw-r--r--octave/rf_vhf_amp.m206
-rw-r--r--octave/rf_vhf_pa.m111
4 files changed, 0 insertions, 431 deletions
diff --git a/octave/rf_bpf.m b/octave/rf_bpf.m
deleted file mode 100644
index e0a39ba..0000000
--- a/octave/rf_bpf.m
+++ /dev/null
@@ -1,37 +0,0 @@
-% rtlsdr_bpf.m
-%
-% David Rowe 24 August 2018
-%
-% Calculate component values for cascaded HP-LP 2-8 MHz Chebychev filter
-%
-% From "RF Circuit Design", Chris Bowick, Ch 3
-
-1;
-
-function C = find_C(Cn, fc, R)
- C = Cn/(2*pi*fc*R);
-endfunction
-
-function L = find_L(Ln, fc, R)
- L = R*Ln/(2*pi*fc);
-endfunction
-
-% 3rd order HP filter, 1dB ripple Cheby, 3MHz cut off, >20dB down at
-% 1MHz to nail strong AM broadcast signals, Table 3-7A. Use a Rs=50,
-% Rl=50, so Rs/Rl = 1. Note we assume a or phantom load in between
-% cascaded HP-LP sections of 50 ohms.
-
-L1 = find_L(1/2.216, 3E6, 50);
-C1 = find_C(1/1.088, 3E6, 50);
-L2 = find_L(1/2.216, 3E6, 50);
-
-printf("L1: %f uH C1: %f pF L2: %f uH\n", L1*1E6, C1*1E12, L2*1E6);
-
-% 3rd order LPF, 8MHz cut off so >30dB down at 21MHz, which aliases back to 7MHz
-% with Fs=28MHz on RTLSDR (14 MHz Nyquist freq). Rs=50, Rl=50, Rs/Rl = 1
-
-C2 = find_C(2.216, 9E6, 50);
-L3 = find_L(1.088, 9E6, 50);
-C3 = find_C(2.216, 9E6, 50);
-
-printf("C2: %f pF L3: %f uH C3: %f pF\n", C2*1E12, L3*1E6, C3*1E12);
diff --git a/octave/rf_design.m b/octave/rf_design.m
deleted file mode 100644
index eae79f6..0000000
--- a/octave/rf_design.m
+++ /dev/null
@@ -1,77 +0,0 @@
-% rfdesign.m
-%
-% David Rowe Nov 2015
-%
-% Helper functions for RF Design
-
-1;
-
-
-% convert a parallel R/X to a series R/X
-
-function Zs = zp_to_zs(Zp)
- Xp = j*imag(Zp); Rp = real(Zp);
- Zs = Xp*Rp/(Xp+Rp);
-endfunction
-
-
-% convert a series R/X to a parallel R/X
-
-function Zp = zs_to_zp(Zs)
- Xs = imag(Zs); Rs = real(Zs);
- Q = Xs/Rs;
- Rp = (Q*Q+1)*Rs;
- Xp = Rp/Q;
- Zp = Rp + j*Xp;
-endfunction
-
-
-% Design a Z match network with a parallel and series reactance
-% to match between a low and high resistance. Note Xp and Xs
-% must be implemented as opposite sign, ie one a inductor, one
-% a capacitor (your choice).
-%
-% /--Xs--+---\
-% | | |
-% Rlow Xp Rhigh
-% | | |
-% \------+---/
-%
-
-function [Xs Xp] = z_match(Rlow, Rhigh)
- assert(Rlow < Rhigh, "Rlow must be < Rhigh");
- Q = sqrt(Rhigh/Rlow -1);
- Xs = Q*Rlow;
- Xp = Rhigh/Q;
-endfunction
-
-
-% Design an air core inductor, Example 1-5 "RF Circuit Design"
-
-function Nturns = design_inductor(L_uH, diameter_mm)
- Nturns = sqrt(29*L_uH/(0.394*(diameter_mm*0.1/2)));
-endfunction
-
-
-% Work out series resistance Rl of series resonant inductor. Connect
-% tracking generator to spec-an input, the series LC to ground. V is
-% the ref TG level (e.g. with perfect 50 ohm term) in volts, Vmin is the
-% minimum at series res freq.
-%
-% /-50-+---+
-% | | |
-% TG C 50 spec-an
-% | | |
-% | L |
-% | | |
-% | Rl |
-% | | |
-% \----+---/
-
-function Rl = find_rl(V,Vmin)
- % at series resonance effect of C and L goes away and we are left with
- % parallel combination of Ls and spec-an 50 ohm input impedance
-
- Rp = Vmin*50/(2*V*(1-Vmin/(2*V)));
- Rl = 1/(1/Rp - 1/50)
-endfunction
diff --git a/octave/rf_vhf_amp.m b/octave/rf_vhf_amp.m
deleted file mode 100644
index 8c5186a..0000000
--- a/octave/rf_vhf_amp.m
+++ /dev/null
@@ -1,206 +0,0 @@
-% s_param_rf.m
-%
-% David Rowe Nov 2015
-%
-% Working for small signal VHF amplifier design using
-% S-param techniques from "RF Circuit Design" by Chris Bowick
-
-rfdesign; % library of helped functions
-
-more off;
-
-Ic = 0.014;
-
-% BRF92 VCE=5V Ic=5mA 100MHz
-
-if Ic == 0.005
- S11 = 0.727*exp(j*(-43)*pi/180);
- S12 = 0.028*exp(j*(69.6)*pi/180);
- S21 = 12.49*exp(j*(147)*pi/180);
- S22 = 0.891*exp(j*(-16)*pi/180);
-end
-
-% BRF92 VCE=10V Ic=14mA 100MHz
-
-if Ic == 0.02
- S11 = 0.548*exp(j*(-56.8)*pi/180);
- S12 = 0.020*exp(j*(67.8)*pi/180);
- S21 = 20.43*exp(j*(133.7)*pi/180);
- S22 = 0.796*exp(j*(-18.5)*pi/180);
-end
-
-% Stability
-
-Ds = S11*S22-S12*S21;
-Knum = 1 + abs(Ds)^2 - abs(S11)^2 - abs(S22)^2;
-Kden = 2*abs(S21)*abs(S12);
-K = Knum/Kden % If > 1 unconditionally stable
- % If < 1 panic
-figure(1);
-clf
-scCreate;
-
-if K < 1
- C1 = S11 - Ds*conj(S22);
- C2 = S22 - Ds*conj(S11);
- rs1 = conj(C1)/(abs(S11)^2-abs(Ds)^2); % centre of input stability circle
- ps1 = abs(S12*S21/(abs(S11)^2-abs(Ds)^2)); % radius of input stability circle
- rs2 = conj(C2)/(abs(S22)^2-abs(Ds)^2); % centre of input stability circle
- ps2 = abs(S12*S21/(abs(S22)^2-abs(Ds)^2)); % radius of input stability circle
-
- s(1,1)=S11; s(1,2)=S12; s(2,1)=S21; s(2,2)=S22;
- plotStabilityCircles(s)
-end
-
-% Gain circle
-
-D2 = abs(S22)^2-abs(Ds)^2;
-C2 = S22 - Ds*conj(S11);
-GdB = 20; Glin = 10^(GdB/10); % lets shoot for 20dB gain
-G = Glin/(abs(S21)^2);
-r0 = G*conj(C2)/(1+D2*G); % centre of gain circle
-p0 = sqrt(1 - 2*K*abs(S12*S21)*G + (abs(S12*S21)^2)*(G^2))/(1+D2*G); % radius of gain circle
-
-scAddCircle(abs(r0),angle(r0)*180/pi,p0,'g')
-printf("Green is the %3.1f dB constant gain circle for gammaL\n",GdB);
-
-% Note different design procedures for different operating points
-
-if Ic == 0.005
- % Choose a gammaL on the gain circle
-
- gammaL = 0.8 - 0.4*j;
-
- % Caclulate gammaS and make sure it's stable by visual inspection
- % compared to stability circle.
-
- gammaS = conj(S11 + ((S12*S21*gammaL)/(1 - (gammaL*S22))));
-end
-
-if Ic == 0.014
-
- % lets set zo (normalised Zo) based on Pout and get gammaL from that
-
- Pout = 0.01;
- Irms = 0.002;
- Zo = Pout/(Irms*Irms);
- zo = Zo/50;
- [magL,angleL] = ztog(zo);
- gammaL = magL*exp(j*angleL*pi/180);
-
- % calculate gammaS
-
- gammaS = conj(S11 + ((S12*S21*gammaL)/(1 - (gammaL*S22))));
-
-end
-
-[zo Zo] = gtoz(abs(gammaL), angle(gammaL)*180/pi,50);
-[zi Zi] = gtoz(abs(gammaS), angle(gammaS)*180/pi,50);
-
-scAddPoint(zi);
-scAddPoint(zo);
-
-% Transducer gain
-
-Gt_num = (abs(S21)^2)*(1-abs(gammaS)^2)*(1-abs(gammaL)^2);
-Gt_den = abs((1-S11*gammaS)*(1-S22*gammaL) - S12*S21*gammaL*gammaS)^2;
-Gt = Gt_num/Gt_den;
-
-if Ic == 0.005
-
- % Lets design the z match for the input ------------------------------
-
- % put input impedance in parallel form
-
- Zip = zs_to_zp(Zi);
-
- % first match real part of impedance
-
- Rs = 50; Rl = real(Zip);
- [Xs Xp] = z_match(Rs,Rl);
-
- % Modify Xp so transistor input sees conjugate match to Zi
- % Lets make Xp a capacitor, so negative sign
-
- Xp_match = -Xp - imag(Zip);
-
- % Now convert to real component values
-
- w = 2*pi*150E6;
- Ls = Xs/w; diameter_mm = 6.25;
- Ls_turns = design_inductor(Ls*1E6, diameter_mm);
- Cp = 1/(w*(-Xp_match));
-
- printf("Transducer gain: %3.1f dB\n", 10*log10(Gt));
- printf("Input: Zi = %3.1f + %3.1fj ohms\n", real(Zi), imag(Zi));
- printf(" In parallel form Rp = %3.1f Xp = %3.1fj ohms\n", real(Zip), imag(Zip));
- printf(" So for a conjugate match transistor input wants to see:\n Rp = %3.1f Xp = %3.1fj ohms\n", real(Zip), -imag(Zip));
- printf(" Rs = %3.1f to Rl = %3.1f ohm matching network Xs = %3.1fj Xp = %3.1fj\n", Rs, Rl, Xs, Xp);
- printf(" with conj match to Zi Xs = %3.1fj Xp = %3.1fj\n", Xs, Xp_match);
- printf(" matching components Ls = %5.3f uH Cp = %4.1f pF\n", Ls*1E6, Cp*1E12);
- printf(" Ls can be made from %3.1f turns on a %4.2f mm diameter air core\n", Ls_turns, diameter_mm);
-
- % Now Z match for output -------------------------------------
-
- Lo = -imag(Zo)/w;
- Lo_turns = design_inductor(Lo*1E6, diameter_mm);
- printf("Output: Zo = %3.1f + %3.1fj ohms\n", real(Zo), imag(Zo));
- printf(" So for a conjugate match transistor output wants to see:\n Rl = %3.1f Xl = %3.1fj ohms\n", real(Zo), -imag(Zo));
- printf(" Which is a series inductor Lo = %5.3f uH\n", Lo*1E6);
- printf(" Lo can be made from %3.1f turns on a %4.2f mm diameter air core\n", Lo_turns, diameter_mm);
-end
-
-
-if Ic == 0.014
- printf("Transducer gain: %3.1f dB\n", 10*log10(Gt));
-
- % Lets design the z match for the input ------------------------------
-
- % put input impedance in parallel form
-
- Zip = zs_to_zp(Zi);
-
- % first match real part of impedance
-
- Rs = 50; Rl = real(Zip);
- [Xs Xp] = z_match(Rl,Rs);
-
- % Lets make Xs a capacitir to block DC, so Xp is an inductor.
- % Modify Xs so transistor input sees conjugate match to Zi. Xs is a
- % capacitor, so reactance is negative
-
- Xs_match = -Xs - imag(Zip);
-
- % Now convert to real component values
-
- w = 2*pi*150E6; diameter_mm = 6.25;
- Li = Xp/w;
- Li_turns = design_inductor(Li*1E6, diameter_mm);
- Ci = 1/(w*(-Xs_match));
-
- printf("Input: Zi = %3.1f + %3.1fj ohms\n", real(Zi), imag(Zi));
- printf(" In parallel form Rp = %3.1f Xp = %3.1fj ohms\n", real(Zip), imag(Zip));
- printf(" So for a conjugate match transistor input wants to see:\n Rp = %3.1f Xp = %3.1fj ohms\n", real(Zip), -imag(Zip));
- printf(" Rs = %3.1f to Rl = %3.1f ohm matching network Xs = %3.1fj Xp = %3.1fj\n", Rs, Rl, Xs, Xp);
- printf(" with Xs a capacitor, and Xp and inductor Xs = %3.1fj Xp = %3.1fj\n", -Xs, Xp);
- printf(" With a conj match to Zi Xs = %3.1fj Xp = %3.1fj\n", Xs_match, Xp);
- printf(" matching components Li = %5.3f uH Ci = %4.1f pF\n", Li*1E6, Ci*1E12);
- printf(" Li can be made from %3.1f turns on a %4.2f mm diameter air core\n", Li_turns, diameter_mm);
-
- % Design output Z match ----------------------------------------------
-
- Rs = real(Zo); Rl = 50;
- [Xs Xp] = z_match(Rl,Rs);
-
- % Lets make XP an inductor so it can double as a RF choke, and Xp as
- % a capacitor will give us a convenient DC block
-
- w = 2*pi*150E6; diameter_mm = 6.25;
- Lo = Xp/w; Lo_turns = design_inductor(Lo*1E6, diameter_mm);
- Co = 1/(w*Xs);
- printf("Output: Zo = %3.1f + %3.1fj ohms\n", real(Zo), imag(Zo));
- printf(" matching network Xp = %3.1f X = %3.1f ohms\n", Xp, Xs);
- printf(" which is parallel Lo = %5.3f uH and series Co = %4.1f pF\n", Lo*1E6, Co*1E12);
- printf(" Lo can be made from %3.1f turns on a %4.2f mm diameter air core\n", Lo_turns, diameter_mm);
-end
-
diff --git a/octave/rf_vhf_pa.m b/octave/rf_vhf_pa.m
deleted file mode 100644
index 000c3fc..0000000
--- a/octave/rf_vhf_pa.m
+++ /dev/null
@@ -1,111 +0,0 @@
-% vhf_pa.m
-%
-% David Rowe Dec 2015
-%
-% Working for 0.5W VHF PA
-
-rfdesign;
-
-% BFQ19 Vce=5V Ic=50mA. These are small signal S-params,
-% which (according to "RF Circuit Design") are not valid.
-% However I need to start somewhere.
-
-S11 = 0.324*exp(j*(-158.1)*pi/180);
-S12 = 0.031*exp(j*(75.9)*pi/180);
-S21 = 19.693*exp(j*(102.7)*pi/180);
-S22 = 0.274*exp(j*(-74.6)*pi/180);
-
-% Lets check stability
-
-Ds = S11*S22-S12*S21;
-Knum = 1 + abs(Ds)^2 - abs(S11)^2 - abs(S22)^2;
-Kden = 2*abs(S21)*abs(S12);
-K = Knum/Kden
-figure(1);
-clf
-scCreate;
-
-if K < 1
- C1 = S11 - Ds*conj(S22);
- C2 = S22 - Ds*conj(S11);
- rs1 = conj(C1)/(abs(S11)^2-abs(Ds)^2); % centre of input stability circle
- ps1 = abs(S12*S21/(abs(S11)^2-abs(Ds)^2)); % radius of input stability circle
- rs2 = conj(C2)/(abs(S22)^2-abs(Ds)^2); % centre of input stability circle
- ps2 = abs(S12*S21/(abs(S22)^2-abs(Ds)^2)); % radius of input stability circle
-
- s(1,1)=S11; s(1,2)=S12; s(2,1)=S21; s(2,2)=S22;
- plotStabilityCircles(s)
-end
-
-
-% determine collector load Rl for our desired power output
-
-if 0
-P = 0.5;
-Vcc = 5;
-w = 2*pi*150E6;
-
-Rl = Vcc*Vcc/(2*P);
-end
-Rl = 10;
-
-% choose gammaL based on Rl
-
-zo = Rl/50;
-[magL,angleL] = ztog(zo);
-gammaL = magL*exp(j*angleL*pi/180);
-
-% calculate gammaS and Zi and plot
-
-gammaS = conj(S11 + ((S12*S21*gammaL)/(1 - (gammaL*S22))));
-[zi Zi] = gtoz(abs(gammaS), angle(gammaS)*180/pi,50);
-
-scAddPoint(zi);
-scAddPoint(zo);
-
-% design Pi network for matching Rl to Ro, where Ro > Rl
-%
-% /---+-Xs1-Xs2-+---\
-% | | | |
-% Rl Xp1 Xp2 Ro
-% | | | |
-% \---+---------+---/
-%
-% highest impedance used to define Q of pi network and determine R,
-% the "virtual" impedance at the centre of the network, whuch is smaller
-% than Rl and Ro
-
-Ro = 50;
-Q = 3;
-R = Ro/(Q*Q+1);
-
-Xp2 = Ro/Q;
-Xs2 = Q*R;
-
-Q1 = sqrt(Rl/R - 1);
-Xp1 = Rl/Q1;
-Xs1 = Q1*R;
-
-Cp1 = 1/(w*Xp1);
-Cp2 = 1/(w*Xp2);
-Ls = (Xs1+Xs2)/w;
-
-printf("Output Matching:\n");
-printf(" Rl = %3.1f Ro = %3.1f\n", Rl, Ro);
-printf(" Q = %3.1f virtual R = %3.1f\n", Q, R);
-printf(" Xp1 = %3.1f Xs1 = %3.1f Xs2 = %3.1f Xp2 = %3.1f\n", Xp1, Xs1, Xs2, Xp2);
-printf(" Cp1 = %3.1f pF Ls = %3.1f nH Cp2 = %3.1f pF\n", Cp1*1E12, Ls*1E9, Cp2*1E12);
-
-% design input matching network between 50 ohms source and 10 ohms at base
-
-Rb = 10; Rs = 50;
-
-[Xs Xp] = z_match(Rb, Rs);
-
-Lp = Xp/w;
-Cs = 1/(w*Xs);
-
-printf("Input Matching:\n");
-printf(" Xs = %3.1f Xp = %3.1f\n", Xs, Xp);
-printf(" Lp = %3.1f nH Cs = %3.1f pF\n", Lp*1E9, Cs*1E12);
-
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