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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 in phase 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. 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 equipment - particularly 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 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 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
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 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 Design by Ajoy Raman |
