Scrambler, ask for discusion and advice.

Hello everyone, at first sorry for my language but i hope you will understand me. Because I'm quite dummy in electronic I was looking for some simple analog scrambler to build it and test it, but when I used google/image searcher I couldn't find no more than 3 simple schematics of scramblers, and I'm wondering why there is only a few simple schematics of this scramblers. For example - if you search amplifier, transmitter or any other device there is such a lot (plenty, many...) simple and hard schematics, and this device (scrambler) I would like to find isn't a lot, and I ask why??? . I have to search different schematics because I must find "that one" in order to have all parts (IC, transistors, diodes etc...) available in my part collection. If I find one schem there is unavailable IC (I don't have one), if I find another schem there is some other part that I don't have. Could you answer me why there is such a few schemes in the web? or maybe you have some quite simple schem I could try to build. The one I found and built is this with 555 timer and 3 transistors made by Andrew Morris but I'm not sure that it is good or bad idea, it works but (maybe I did some wrong) but during scrambling and descrambling I hear some unwanted squeak ( should it be that???). It codes voice quite well but after decoding this squeak is no good for ears. Do you have some advice for me what to do better or ....???, thanks a lot for answer or discusion. Bye.