180 PRINT: INPUT "USE CAPITALS. WANT EXPLANATION (Y/N)"; Q$: IF Q$<>"Y" THEN 560
190 CLS: PRINT "THIS PROGRAM DETERMINES IF MIXING (SUM AND DIFFERENCE) PRODUCTS OF 'M' TIMES
200 PRINT "A LOCAL OSCILLATOR FREQUENCY (LO) AND 'N' TIMES SIGNALS IN CRITICAL FREQUENCY
210 PRINT "BANDS OF CONCERN WILL FALL IN A SPECIFIED OUTPUT FREQUENCY BAND.": PRINT
220 PRINT "ALL COMPUTED RESULTS SHOULD NORMALLY BE DIRECTED TO THE PRINTER BECAUSE OF THE
222 PRINT "VOLUME OF OUTPUT. HOWEVER LISTING CAN BE DIRECTED TO THE MONITOR SCREEN. THIS
223 PRINT "IS RECOMMENDED ONLY FOR SHORT SEARCHS - NOT DIRTY LO CASE.": PRINT
230 PRINT "THE PROGRAM FIRST ASKS FOR THE 'DATE' AND 'TITLE'. THESE MY BE SKIPPED BY
240 PRINT "PRESSING CARRIAGE RETURNS. THE DATE AND TITLE ENTERED WILL APPEAR AT THE TOP
250 PRINT "OF EACH PAGE OF PRINTED RESULTS": PRINT
260 PRINT "THE PROGRAM CONSIDERS BOTH 'CLEAN' AND 'DIRTY' LO CASES.": PRINT
270 PRINT "IN THE CLEAN LO CASE, IT IS ASSUMED A SINGLE LO FREQUENCY EXISTS FROM WHICH
280 PRINT "HARMONICS ARE GENERATED BY A (MIXER'S) NON-LINEARITY.": PRINT: PRINT "IN THE DIRTY LO CASE, IT IS ASSUMED THAT THE LO IS GENERATED FROM A LOWER
290 PRINT "FREQUENCY (FP) CRYSTAL OSCILLATER AND THAT SPURIOUS MULTIPLES OF FP AT
300 PRINT "FREQUENCIES OTHER THAN THE LO ARE PRESENT AT THE (MIXER'S) LO INPUT.": PRINT: INPUT "PRESS CARRIAGE RETURN TO CONTINUE"; Q$: PRINT
310 PRINT "IF THE DIRTY LO CASE IS SELECTED, THE PROGRAM ASKS FOR FP. IT THEN DIVIDES
320 PRINT "THE LO FREQ BY FP TO MAKE SURE IT IS AN INTEGRAL FACTOR. IF FP IS NOT AN
330 PRINT "INTEGRAL FACTOR, IT WILL ROUND FP TO MAKE IT ONE. THE PROGRAM THEN LOOKS
340 PRINT "FOR M X N PRODUCTS IN THE SPECIFIED OUTPUT BAND FOR ALL HARMONICS OF FP UPTO A
350 PRINT "DESIGNATED LIMIT (MAX HARMONIC). IN ESSENCE THE CLEAN LO CALCULATION IS REPEATED
360 PRINT "FOR EVERY POSSIBLE SPURIOUS LO COMPONENT.": PRINT
370 PRINT "THE PROGRAM REQUESTS THE LOWER AND UPPER EDGES OF THE OUTPUT FREQ BAND. ALL
380 PRINT "FREQUENCIES ARE NORMALLY ENTERED IN MHz, ALTHOUGH ANY FREQUENCY UNITS MAY BE
390 PRINT "USED AS LONG AS ALL FREQUENCIES ARE SPECIFIED IN THE SAME UNITS.": PRINT
400 PRINT "THE PROGRAM ALLOWS ANY NUMBER OF CRITCAL BANDS TO BE ENTERED. THESE ARE FREQ
410 PRINT "BANDS IN WHICH SIGNALS COULD ENTER THE SYSTEM AND MIX WITH THE LO. TYPICAL BANDS
420 PRINT "OF CONCERN ARE THE INPUT FREQUENCIES OF THE MIXER, UNFILTERED FREQUENCIES NEAR
430 PRINT "THE INPUT BAND, THE MIXER OUTPUT BAND, HIGH LEVEL SIGNAL SOURCES NEAR THE MIXER,