@Rama: Thanks for your nice blogs.It is heartening to note a number DIYs keeping this alive and kicking.
Thank you for your kind words -- I must admit that by aroudn 2000 i was starting to get worried that hobby electronics was on the way out -- but then the Maker Movement suddenly went mainstream and now building things is cool again (Happy Dance)
Max, It was in 1983 that Elektor published the first hardwired modular(op amp and CMOS logic IC based) real time spectrum analyser display article using a Futaba VF Display (14X10 dot matrix display used for lift panel display). At about the same time, Itron, NEC and futaba also developed multicolor VFD spectrum analyser displays which were much more attractive than the colour LCDs used thesedays. May be future OLED displays may match their beauty.The dots were actually small(1mmx5mm) coloured rectangular tidbits and glew in bright green, lemon and red colours. Blue and orange were added later. The tidbits were so cute that one felt like picking them off the display and eating them.A little later, SCF (switched capacitor filter) technology has become popular and digital clock based filters were cried to be used in HAM radio, and audio spectrum analyser filter applications.Exar has pioneered these ICs (along with EG and G Reticon R6520) in the form of XR1092 and other ICs.Sanyo has then designed several Integrated spectrum analyser with display driver ICs with I2C interface. EXAR's SCF line got affected as there was some problem with ROHM, which was their foundry then.ROHM also made BA series of SCF filter ICs.National and Max made a number of SCF ICs. NJRC (New japan Radio corp) has then developed a serial audio DSP which was dedicated for digital audio spectrum analyser application and was obsoleted about a decade ago.Yamaha also had a similar series of serial DSP ICs.Fortunately, Mixed signal integration continues making these wonderful SCF ICs available. Even now a number of branded graphic equalisers with VFD spectrum analyser are traded on ebay.
Thanks for your nice blogs.It is heartening to note a number DIYs keeping this alive and kicking.
It was the name of course that I'm talking about :-) reminds me of an April 1st edition of Electronics Australia back in the 70's where a bunch of much more believable acronyms were similarly well chosen.