Radio circuit noticeboard

Radio circuit noticeboard: 

https://padlet.com/seanhaddps/the-radio-board-hwqnn4bdb7gakotq


Friday jokes:

https://padlet.com/seanhaddps/friday-jokes-im2scj4ac7bnjbwe

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Neon Bulb Oscillators

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Neon Tube Oscillators  Fig. 1 High voltage to headphones, don't do this in modern times. Very high impedance headphones are implied. A neon bulb is useful in many ways in an amateur station, but there are undoubtedly many amateurs who are not aware of the fact that the device can be made to oscillate at either audio or radio frequencies. Fig. 1 shows how a single bulb may be hooked up as an audio frequency oscillator. The L-C circuit is formed by the headphones and a condenser, and by varying the capacity the circuit can be made to oscillate at frequencies from a few cycles per second up to the highest audio frequencies.  The variable resistor in series with the bulb and battery controls the strength of oscillation, and also controls the frequency to some extent. A 1 nf variable condenser will be sufficient to cover most of the audio range.  Fig. 2 The circuit in Fig. 2 may be used when an RF oscillator is to be modulated at audio frequencies. The transformer may be an or...
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 A whiteboard view: You can take a decision matrix view of ReLU neural networks. Instead of ReLU(Wx) you create a diagonal matrix with binary 1 or 0 entries according to the ReLU decisions (x>=0?) Then conceptually a layer is DWx. Where D is doing row selection on W. And in fact D does column selection on the weight matrix in the next layer. That is very coarse parameter selection which is linear mapping selection.
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Q Multiplier Circuits

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Q Multipliers Q multipliers were commonly used in amateur radio circuits in the past, especially in shortwave receivers. They were used to improve the selectivity and sensitivity of the receivers, making it possible to receive weaker signals and to distinguish between signals that were close together in frequency. Here are some specific examples of amateur radio circuits from the past that used Q multipliers: The Heathkit AR-3 receiver, which was a popular shortwave receiver in the 1950s, had a built-in Q multiplier. The Drake 2B receiver, which was another popular shortwave receiver in the 1950s and 1960s, had a separate Q multiplier unit that could be added to the receiver. The Collins KWS-1 transmitter, which was a popular amateur radio transmitter in the 1960s and 1970s, used a Q multiplier to generate the SSB signal. From Zero To Off-Grid Hero (sponsored) Operation By cancelling out the resistance and other losses in an LC (aka LCR) circuit its Q (voltage magnification at resonant...
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