K2 RF Speech Processor?
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I asked this question about 1.5 years ago and still have not heard from
anyone with real experience... Has anyone tried any of the DF4ZS RF speech processors (http://jwm.de/afu/index0.htm) with a K2 yet? For those who think the SSB "punch" is a little weak, maybe this would help. In fact, maybe this would be a good Mini-Module Kit. 73, Henry - K4TMC K2/100's 3137 and 4796 _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K2 RF Speech Processor?
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Henry, [hidden email] , wrote:
> Has anyone tried any of the DF4ZS RF speech processors > (http://jwm.de/afu/index0.htm) with a K2 yet? > > For those who think the SSB "punch" is a little weak, maybe this would > help. > In fact, maybe this would be a good Mini-Module Kit. -------------------------------------------------------------------------- Great idea! Although I have not used DF4ZS's speech processor, I have used various forms of this type of audio processor and RF clippers over the years and have found that they are useful, perhaps more so than low cost (not studio) audio compression devices. Personally if I intended to buy one of his processors I would go for the larger external unit, because reasonably good SSB filters should be used before and after the RF clipping circuits, all followed by an audio low pass filter at the output with a cutoff around 3kHz, all of which I believe he has included in the larger unit. This could of course be done with a smaller unit which included these items, but is there enough space inside the K2 to fit it in? Also the processor should be shielded to avoid the risk of RF feedback, and prevent the processor's LO signal from getting out. When used with a K2, I suspect that the K2's audio compressor should be set for a small degree of compression, if any, and most / all of the audio processing done by the RF clipper - just an unproven hunch. 73, Geoff GM4ESD _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Geoffrey Mackenzie-Kennedy wrote:
> Henry, [hidden email] , wrote: > >> Has anyone tried any of the DF4ZS RF speech processors >> (http://jwm.de/afu/index0.htm) with a K2 yet? >> >> For those who think the SSB "punch" is a little weak, maybe this >> would help. >> In fact, maybe this would be a good Mini-Module Kit. > > -------------------------------------------------------------------------- > > > Great idea! Although I have not used DF4ZS's speech processor, I have > used various forms of this type of audio processor and RF clippers > over the years and have found that they are useful, perhaps more so > than low cost (not studio) audio compression devices. Personally if I > intended to buy one of his processors I would go for the larger > external unit, because reasonably good SSB filters should be used > before and after the RF clipping circuits, all followed by an audio > low pass filter at the output with a cutoff around 3kHz, all of which > I believe he has included in the larger unit. This could of course be > done with a smaller unit which included these items, but is there > enough space inside the K2 to fit it in? Also the processor should be > shielded to avoid the risk of RF feedback, and prevent the processor's > LO signal from getting out. > > When used with a K2, I suspect that the K2's audio compressor should > be set for a small degree of compression, if any, and most / all of > the audio processing done by the RF clipper - just an unproven hunch. > > 73, > Geoff > GM4ESD > > speech compression device, not a clipper. Compression increases average power used and sounds louder. If set too high it sounds odd and can create clipping that generates unwanted sidebands. On my radio I run compression all the time. It works in conjunction with the Automatic Linearity Control the radio has. If you don't have ALC it is harder to set the Compression. 73 Karl K5DI _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K2 RF Speech Processor?
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Karl Larsen, K5DI wrote:
> Hi Geoff, I would suggest if your making a mini-module let it be a > speech compression device, not a clipper. Compression increases average > power used and sounds louder. If set too high it sounds odd and can create > clipping that generates unwanted sidebands. > > On my radio I run compression all the time. It works in conjunction > with the Automatic Linearity Control the radio has. If you don't have ALC > it is harder to set the Compression. ------------------------------------------------------------- Hi Karl. A moot point!! I'll have to get back to you later today as I must get out to mow down the grass, mutating into elephant grass. With my K2/100 I use the audio compressor and a 'flicker' of ALC, but RF clipping and again a 'flicker' of ALC in the homebrew rig. One has to be very careful not to use too much ALC - other problems can arise. My apology for my haste, will reply later. 73, Geoff GM4ESD _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Hi Geoff, cut your weeds and we can both think hard on what "Speech
Compression" really is. I got to thinking and about all it can be is clipping of the high voice peaks, and increasing audio drive. I will look at the ARRL Hand Book and see what they have. 73 Karl K5DI Geoffrey Mackenzie-Kennedy wrote: > Karl Larsen, K5DI wrote: > >> Hi Geoff, I would suggest if your making a mini-module let it be a >> speech compression device, not a clipper. Compression increases >> average power used and sounds louder. If set too high it sounds odd >> and can create clipping that generates unwanted sidebands. >> >> On my radio I run compression all the time. It works in >> conjunction with the Automatic Linearity Control the radio has. If >> you don't have ALC it is harder to set the Compression. > > ------------------------------------------------------------- > > Hi Karl. A moot point!! I'll have to get back to you later today as I > must get out to mow down the grass, mutating into elephant grass. > > With my K2/100 I use the audio compressor and a 'flicker' of ALC, but > RF clipping and again a 'flicker' of ALC in the homebrew rig. One has > to be very careful not to use too much ALC - other problems can arise. > > My apology for my haste, will reply later. > > 73, > Geoff > GM4ESD > > > > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Karl Larsen wrote:
> Hi Geoff, cut your weeds and we can both think hard on what "Speech > Compression" really is. I got to thinking and about all it can be is > clipping of the high voice peaks, and increasing audio drive. I will > look at the ARRL Hand Book and see what they have. In the AM days, many hams incorporated simple diode audio clippers in their modulators to clip the negative-going peaks of the audio signal, followed by lowpass filters to clean up the high-frequency distortion products produced by clipping. This permitted a higher level of modulation in the positive direction without splatter, thus increasing the average power in the signal. Some amount of compression was often used as well in order to increase the average modulation percentage. Processed AM signals sounded much louder without significant widening if the processing was done properly. When SSB came along, it was found that audio peak clipping did not have the desired result, because the height of the peaks in the RF envelope did not correspond directly to the audio envelope. So RF clipping came into use in which the clipping and filtering takes place after the generation of the SSB (or at least DSB) signal. AS Geoff points out, if you want to do this in the audio chain, you need to generate an RF signal, clip and filter it, and then convert it back to audio. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K2 RF Speech Processor?
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In reply to this post by Karl Larsen
the K2 already has a "variale compression and noise gate " chip for the mic preamp... analog devices SSM2165-1 see: http://www.analog.com/UploadedFiles/Data_Sheets/2864404SSM2165_b.pdf#search=%22ssm2165-1%22 I too would be interested to see how much additional ""distortionless"" average amplitude could be generated beyond the AD chip. bill ny9h _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K2 RF Speech Processor?
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Hi,
I have modified my K2 with the internal SSM2165. With the SSBC-Menu I can choose the compression 1:1 (1:1), 3:1 (2:1), 6:1 (3:1) and 9:1 (4:1) - the original in bracket -. The mod is very easy: You change RP5 to a 150k and connect Pin 2 and Pin 3 of RP5. Thats all! You find the mode in 'QRP-Report' 3/2004 (only in german). For interest, I can send a pdf. 72 Karl-Heinz, DF7KHK _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Smooth Voice Controller? was K2 RF Speech Processor?
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In reply to this post by k4tmc
And along the same lines, what about a better VOX?
The Smooth Voice Controller from April 1992 QST used a bucket brigade audio delay system to prevent any audio from being chopped off by the VOX. A QSK system for voice. Probably lots of better technology exists now than 14 years ago when that article was written by John Cowan, W4ZPS. Would also make a good Mini-Module Kit. Darrell VA7TO K2#5093 On September 8, 2006 06:26 pm, [hidden email] wrote: > For those who think the SSB "punch" is a little weak, maybe this would > help. In fact, maybe this would be a good Mini-Module Kit. -- Darrell Bellerive Amateur Radio Stations VA7TO and VE7CLA Grand Forks, British Columbia, Canada _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Bill Steffey NY9H
Thanks Bill for all the information and the fact that the K2 has a
chip from Analog Devices that should do the desired job. I have the pdf thanks Bill and will study that with interest. A question. Does the K2 have a variable resistor at R! Compression ratio set? 73 Karl Bill NY9H wrote: > > the K2 already has a "variale compression and noise gate " chip for > the mic preamp... analog devices SSM2165-1 > see: > http://www.analog.com/UploadedFiles/Data_Sheets/2864404SSM2165_b.pdf#search=%22ssm2165-1%22 > > > I too would be interested to see how much additional ""distortionless"" > average amplitude could be generated beyond the AD chip. > > bill ny9h > > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K2 RF Speech Processor?
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Hi Karl,
> A question. Does the K2 have a variable resistor at R! Compression > ratio set? Yes, the resistors RP5 are the 'variable' resistors for compression. Yesterday I had send a mode for other compressions. With other resistors you make your own three compressions. 73/72 de Karl-Heinz, DF7KHK _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K2 RF Speech Processor?
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In reply to this post by Karl Larsen
Karl Larsen <[hidden email]> wrote:
> Hi Geoff, cut your weeds and we can both think hard on what "Speech > Compression" really is. I got to thinking and about all it can be is > clipping of the high voice peaks, and increasing audio drive. I will look > at the ARRL Hand Book and see what they have. ---------------------------------------------------------------- Hi Karl, My apology for my delay in getting back to you earlier, as a Scottish poet wrote -'The best laid plans of mice ......... The end result of compression or clipping is essentially the same, which is that the peak to average power ratio of the output signal is less than the peak to average power ratio of the input signal, assuming that 'compression' *is* taking place likewise clipping (slicing). This obviously means that the average power of the signal is in both cases increased. Compressors, frequently appearing under different names, achieve the result more 'gently' than clippers, and there is some delay before they react in part due to the time constants within the gain control loop. Whether or not this delay results in any performance problem is something that the designer will have checked, and in the K2 there does not appear to be a problem. You will have seen that in the SSM2165 chip the sample of the signal used to control gain is taken from a point ahead of the gain controlled amplifier, the VCA. This method of 'forward control' makes it much easier to have the controlled amplifier's gain set suitably for a signal as it arrives. The picture is of course more complex in real life because many signals of various amplitudes and frequency occupy the same time frame. Those systems using 'backward' control, such as a typical ALC where the control sample is taken from the output, by their very nature will allow some output, perhaps distorted, before the gain of the controlled amplifier is reduced - closing the barn's door after the horse has bolted. Thus in my view, ALC is useful if used carefully and as the last line of defence. Clippers, assuming proper design, react very quickly slicing the signal at the required amplitude. If used directly at audio the result can be a mess of harmonics and intermod products. For this reason an audio signal is upconverted to become a SSB RF signal, symmetrically clipped, filtered and downconverted back to audio. With a reasonable RF SSB filter before the clipper to obtain unwanted sideband suppression and another after the clipper to attenuate harmonics and to limit bandwidth , some intermodulation products within this second filter's passband will remain. In practice their effect is acceptable provided that a low pass audio filter with a cutoff frequency around 3 kHz is added to the output. One function of this audio filter is to attenuate any intermod products resulting from the RF to audio downconversion which are outside of the required audio passband. Of course the clipping and filtering can be applied to a transmitter's IF SSB signal instead. I admit to oversimplifying the picture. 73, Geoff GM4ESD _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Karl-Heinz Kaatz, DF7KHK
Karl-Heinz Kaatz, DF7KHK wrote:
> Hi Karl, > >> A question. Does the K2 have a variable resistor at R! Compression >> ratio set? > > Yes, the resistors RP5 are the 'variable' resistors for compression. > > Yesterday I had send a mode for other compressions. With other > resistors you make your own three compressions. > > 73/72 de > Karl-Heinz, DF7KHK > > buddy Heinz Gelhaar. We had a lot of fun together. The K2 has a Analog Devices SSM2165* which is a 8 pin chip with external capacitors and one resister. The values of the capacitors is the result of a design calculation. It sets up the internal amplifiers to work over the actual audio input levels. It can serve as a mike input amplifier to a SSB transmitter. This might explain the problems people are having with various mike's not working well on the K2. The SSM2165 wants a design center mike input signal to work well. The Compression Ratio set resistor does set the compression in this device and since it's there it can be experimented with. So it is safe to say the K2 already has speech compression built in. 73 Karl K5DI _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K2 RF Speech Processor?
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In reply to this post by Bill Steffey NY9H
Bill NY9H <[hidden email]> wrote:
> I too would be interested to see how much additional ""distortionless"" > average amplitude could be generated beyond the AD chip. ------------------------------------------------------------ FWIW my guess is that if audio compression and true clipping is to be employed before the balanced modulator, it's an 'either - or' situation. If some of both is used, the clipper should I think be ahead of the compressor mainly to take advantage of the existing noise gate in the K2's compressor, but not a tidy arrangement. I still have the hunch that if a clipper is used as the 'main' audio processor, the compressor's compression ratio should be reduced. To limit additional distortion could require a symmetrical clipper in the Tx IF together with the audio compression, but that is a very different story, and quite impractical as a mod to the K2. 73, Geoff GM4ESD _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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