DDS forms Inphase & Quadrature Generator - 12/04/97 EDN-Design Ideas Many instrumentation applications use two sine waves to carry out coherent modulation. The circuit in Figure 1 allows you to measure vector magnitudes (for example, voltage or impedance) by multiplying the measured signal with inphase and quadrature sinusoidal signals of the same frequency. In a classic approach, these signals come from one VCO and a pi/2 (90º) delay. However, when the measurements cover a wide frequency span, it is necessary to compensate phase differences between the measured and instrument circuits by using a programmable delay.__ Circuit Design by J Toda, R Bragos, and M Tresanchez, UPC, Barcelona, Spain
Delay Unit for Surround Sound - The Mitsubishi M65830 Delay IC has been discontinued (for reasons beyond my comprehension) , and so far a suitable replacement device has not been found. This means (of course) that you will be unable to build this delay circuit. I have left the project in place as reference, and the overall connection schematic is still valid if (when?) a replacement for the M65830 is located. The project will be updated at that time. In the meantime, just ignore the delay circuit __ Designed by Rod Elliott ESP
Equivalent Transistors - below is a list of equivalent transistors for use in early solid state Quad equipmentparticularly the 33 and 303 (Many thanks to Michael Coatham for sending me the data) __ Designed by quadworld @ reocities.com
Equivalent valves - below is a list of equivalent valves for use in vintage Quad hifi, that offer very little or no reduction in performance and will not damage the equipment itself __ Designed by quadworld @ reocities.com
Low-Cost Quadraphonic Amplifier - Here is a circuit for a simple but useful low-cost quadraphonic (having four channels) amplifier. It can be used for experiments in open or closed spaces, including small home labs and __ Electronics Projects for You
Quad 303 - This is the schematic only __ Designed by quadworld @ reocities.com
Quad 405 - This is the schematic only __ Designed by quadworld @ reocities.com
Quad II - schematic only
Quadraphonic Amplifier - This is a four channel amplifier ideally suited for use with quadraphonic equipment such as a Sound Blaster Live card. There is no volume control, audio levels being directly controlled from the sound card itself. __ Designed by Andy Collison
Quadrature (sine/cosine) voltage controlled oscillator - Several schematics on this page, scroll to find this one. The first circuit is a dual ramp generator where the positive and negative ramps are generated separately. This circuit was used as a ramp generator for a transistor curve tracer: the positive going ramp was used for testing NPN transistors and the negative ramp for testing PNP transistors. __ Designed by Richard Torrens
Simple Circuit Surround Processor - Simple Surround Processor. This is built with only conventional parts, and digital delay block, too. So it is very easy to build. __ Designed by The Electronic Lives Manufacturing-presented Chan
Simple Circuit Surround Sound Decoder - This surround-sound decoder is based on the "Hafler" principle, first discovered by David Hafler sometime in the early 1970s. The original idea was to connect a pair of speakers as shown in Figure 1, for use as the rear speakers in the surround setup __ Designed by Rod Elliott ESP
SM Quadrature Couplers have high performance, Low cost - AN-30-003 App Note __ MiniCircuits.com
Surface Mount LTCC Quadrature Splitters - AN-10-005 App Note __ MiniCircuits.com
Surround Effect - First, check out your existing stereo system to see if it already accommodates surround sound. Many systems, even some low cost mini units, already have connections for matrix surround. If you see an additional pair of speaker jacks (usually labelled "rear") in the back of the unit, then you most likely have surround sound capabilities built-in to your current gear. Many such systems also have a switch labelled "two-by-two matrix" or "matrix surround". This has to be switched on, after the additional speakers have been attached, to activate the matrix circuit. __ Designed by Chris Kantack
Surround Processor - Simple Surround Processor. This is built with only conventional parts, and digital delay block, too. So it is very easy to build. __ Designed by The Electronic Lives Manufacturing-presented Chan
Surround Sound Decoder - This surround-sound decoder is based on the "Hafler" principle, first discovered by David Hafler sometime in the early 1970s. The original idea was to connect a pair of speakers as shown in Figure 1, for use as the rear speakers in the surround setup __ Designed by Rod Elliott ESP
Surround Sound Digital Delay Unit - The Mitsubishi M65830 Delay IC has been discontinued (for reasons beyond my comprehension) , and so far a suitable replacement device has not been found. This means (of course) that you will be unable to build this delay circuit. I have left the project in place as reference, and the overall connection schematic is still valid if (when?) a replacement for the M65830 is located. The project will be updated at that time. In the meantime, just ignore the delay circuit __ Designed by Rod Elliott ESP
Two Quadrant Analog Multiplier uses No Log Amps - 10/10/96 EDN-Design Ideas You usually obtain product of two values by summing outputs of logarithmic amplifiers. block diagram in Figure 1 shows a configuration that produces a two-quadrant product of analog signals but uses no log amplifiers. VA and VB are multiplier inputs. triangle generator produces a linear triangle whose voltage range is between0V and maximum value that VB can attain (VB>=0V]. VA may assume both positive and negative values. Figure 2 shows circuit waveforms__ Circuit Design by Giovanni Romeo, Istituto Nazionale di Geofisica, Rome, Italy
Two-quadrant multiplying DAC utilizes octal CMOS
buffer - 09/30/13 EDN-Design Ideas Here's a novel approach to making a multiplying DAC__ Circuit Design by Ajoy Raman |