The Lowpassfilter is designed with ADDE-Filterdesign.įrequency curve of the IF filter realized by 3 crystals.ĭ AF-preamplification with automatic gain control for the AF.īandscan on mediumwave on a novemberevening 2013. R1 is the attenuator in order to avoid distortions. DE681530C DET50144D DET0050144D DE681530C DE 681530 C DE681530 C DE 681530C DE T50144 D DET50144 D DE T50144D DE T0050144 D DET0050144 D DE T0050144D DE 681530 C DE681530 C DE 681530C Authority DE Germany Prior art keywords filter crystal bandwidth resonance terminating Prior art date Legal status (The legal status is an assumption and is not a legal conclusion. The lowpass filter in the frontend in order to supress the mirror frequency. The former operates on a higher-level, known signal in a known setting, while the latter must find and decode a largely unknown signal corrupted by internal and external noise, interference. A transmitter has much-less challenging task than the receiver. The groundig is made by a piece of aluminium foil. Carlyle Barton Laboratory technical reports Theory of Sequential Filtering and Its Application to Signal Detection and Classification (AF-8) by Blasbalg, H. Radio receiver architectures, Part 1TRF and Superhet. The IF amplifier for a superhet or superheterodyne radio provides the main gain and adjacent channel filtering, and requires careful analyis of the requirements. The receiver was built in the manhattan style technique. A good grounding avoids unwanted oscillation and hum.
I realized the receiver in the manhattan style circuit technique. This receiver needs only some fixed inductors. This superheterodyne for medium wave has a crystal filter with about 6 kHz bandwith an a center frequency of 4,4 MHz, which is is also the IF.
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