I’m interested in why it is that a series of resistors totalling at certain resistance should have more noise than a single resistor of the same value. For example why would 10 x 10K resistors have more noise than a single 100K resistor? The insulating paint of a resistor can be scraped off to reveal the underlying resistive film and it is possible to run a multimeter along the film to vary the resistance, much like a potentiometer. If this resistor was divided into 10ths it is essentially the 10 resistors simply joined end to end without the caps and leads. Larger value resistors are generally spiral cut to gain the resistive value in a small package, leading to higher inductance. Hence in some applications smaller resistors in series may be beneficial (or preferably SMDs).
Interested to hear comments.
Cheers,
Pete
Interested to hear comments.
Cheers,
Pete
Alaskanaudio,
Useful circuit, but when this http://www.usdigital.com/products/ls7083-84/ costs $3 or so, is it worth the extra effort, space, etc, to build?
Jakeh
Useful circuit, but when this http://www.usdigital.com/products/ls7083-84/ costs $3 or so, is it worth the extra effort, space, etc, to build?
Jakeh
When controlling the CS3310/PGA2310, you probably are going to use a microcontroller. Then it is not necessary to use circuitry to convert the information from the rotary encoder to up/down pulses, because this determining can be done with the microprosessor. I don't remember how, but I did see some code about that sometime ago.
There's also a rotary encoder that outputs pulses directly (if I got the thing right). I remember it was Alps SRBM series of encoders or something. I believe it can be used to replace the up/down buttons without any extra components. But it is more expensive than a "regular" encoder.
I was surprised when I looked at the CS3310 controlling code in the link mlloyd1 posted. I thougt the code would be much more complicated. I'm very interested in things that are related to controlling the CS3310, decoding remote controller signals and also decoding the rotary encoder. So, if you have good information / links about these things, please post them!
Janne
[Edited by Janne Nivala on 10-26-2001 at 09:58 AM]
There's also a rotary encoder that outputs pulses directly (if I got the thing right). I remember it was Alps SRBM series of encoders or something. I believe it can be used to replace the up/down buttons without any extra components. But it is more expensive than a "regular" encoder.
I was surprised when I looked at the CS3310 controlling code in the link mlloyd1 posted. I thougt the code would be much more complicated. I'm very interested in things that are related to controlling the CS3310, decoding remote controller signals and also decoding the rotary encoder. So, if you have good information / links about these things, please post them!
Janne
[Edited by Janne Nivala on 10-26-2001 at 09:58 AM]
I found something about decoding a rotary encoder:
http://mechsys2.me.berkeley.edu/ME235/LabFiles/QuadRat1.html
http://www.sxlist.com/techref/microchip/language/c/io/qenc-dk.htm
(a link from http://www.sxlist.com/techref/microchip/qenc.htm)
Janne
http://mechsys2.me.berkeley.edu/ME235/LabFiles/QuadRat1.html
http://www.sxlist.com/techref/microchip/language/c/io/qenc-dk.htm
(a link from http://www.sxlist.com/techref/microchip/qenc.htm)
Janne
jteef had asked for an explanation of the serial port.
The PGA2310 uses a synchronous serial port, which means there is a clock line and at least one data line (on the PGA2310, the other data line is an output). Data is "clocked in", meaning that the microprocessor does the followng steps:
1. The clock line SCLK is set to a 0.
2. The first bit's value is placed on the data line SDI.
3. SCLK is set to a 1. The PGA2310 loads the value of SDI and stores it somewhere.
4. After a slight delay, SCLK is set back to 0.
5. Steps 2-4 are repeated for all the other data bits.
The port is "serial" because only one data line is used (parallel would mean more than one bit is read at a time, therefore more wires).
The port is "synchronous" because the clock signal is used to synchronize the data transfer. Speed of the transfer can vary over a huge range. Asynchronous, like a PC COM1 port, doesn't use a clock but must time everything carefully (the baud rate must be fixed).
The PGA2310 has other pins, the CS and SDO lines that are used when you are running more than one device.
The PGA2310 uses a synchronous serial port, which means there is a clock line and at least one data line (on the PGA2310, the other data line is an output). Data is "clocked in", meaning that the microprocessor does the followng steps:
1. The clock line SCLK is set to a 0.
2. The first bit's value is placed on the data line SDI.
3. SCLK is set to a 1. The PGA2310 loads the value of SDI and stores it somewhere.
4. After a slight delay, SCLK is set back to 0.
5. Steps 2-4 are repeated for all the other data bits.
The port is "serial" because only one data line is used (parallel would mean more than one bit is read at a time, therefore more wires).
The port is "synchronous" because the clock signal is used to synchronize the data transfer. Speed of the transfer can vary over a huge range. Asynchronous, like a PC COM1 port, doesn't use a clock but must time everything carefully (the baud rate must be fixed).
The PGA2310 has other pins, the CS and SDO lines that are used when you are running more than one device.
Optical Shaft Encoder Decoder IC
The part show in your link is indeed much simpler to use than building a optical shaft encoder decoder from scratch. Using this IC or one like it would of course be the prefered way to get the decoding job done.
The part you mention has my interest and I have filed the data sheet in my reference files for potential future use.
There are still things that can be learned from building a block with the same basic functions from a hand full of parts that may be laying around in ones junk box.
Thank you for the lead on this part,
John Fassotte
Alaskan Audio
Jakeh said:
The part show in your link is indeed much simpler to use than building a optical shaft encoder decoder from scratch. Using this IC or one like it would of course be the prefered way to get the decoding job done.
The part you mention has my interest and I have filed the data sheet in my reference files for potential future use.
There are still things that can be learned from building a block with the same basic functions from a hand full of parts that may be laying around in ones junk box.
Thank you for the lead on this part,
John Fassotte
Alaskan Audio
digital volume
hi.
it seems to me that few (if any) is paying attention to the indication of the actual volume setting.
even the simplest remote volume controls (a tv or whatever) are doing that and i think its important and nice to see the volume level , we did some work on this a couple of years back and precise indication proved to me as much of a task as the volume control(s) itself.
any good ideas or input??
k madsen - km_cad@yahoo.com
hi.
it seems to me that few (if any) is paying attention to the indication of the actual volume setting.
even the simplest remote volume controls (a tv or whatever) are doing that and i think its important and nice to see the volume level , we did some work on this a couple of years back and precise indication proved to me as much of a task as the volume control(s) itself.
any good ideas or input??
k madsen - km_cad@yahoo.com
Yes, a microcontroller is by far the best way to control one of these digital volume chips and provide a readout of the volume setting.
Microcontrollers are far easier to use than you may think. The primary barrier is usually a psychological one. Once you get past the initial learning curve (which can seem intimidating at first), micros turn out to be very simple and easy to use. The easiest to use are the Microchip PIC and Atmel AVR series chips. Development software for both of these are free, and you don't necessarily need an expensive programmer to download your code into them... almost all of the AVR series can be programmed from your PC using in-circuit serial programming, and there are several PIC chips which can also be programmed in-circuit, using a simple serial port adapter you can build for $3 or so. If you visit the respective mfg's websites, you'll find plenty of good info and appnotes, plus code samples and so forth.
There is a good book which i used to learn about micros... can't remember the title right now, but the author was Myke Predko. I think he even has a website. Anyway, I'm sure it's just one of several good books which can provide the necessary introductory info. A search on Amazon will likely reveal several well-reviewed books which are more up to date than the book I mentioned.
Microcontrollers are far easier to use than you may think. The primary barrier is usually a psychological one. Once you get past the initial learning curve (which can seem intimidating at first), micros turn out to be very simple and easy to use. The easiest to use are the Microchip PIC and Atmel AVR series chips. Development software for both of these are free, and you don't necessarily need an expensive programmer to download your code into them... almost all of the AVR series can be programmed from your PC using in-circuit serial programming, and there are several PIC chips which can also be programmed in-circuit, using a simple serial port adapter you can build for $3 or so. If you visit the respective mfg's websites, you'll find plenty of good info and appnotes, plus code samples and so forth.
There is a good book which i used to learn about micros... can't remember the title right now, but the author was Myke Predko. I think he even has a website. Anyway, I'm sure it's just one of several good books which can provide the necessary introductory info. A search on Amazon will likely reveal several well-reviewed books which are more up to date than the book I mentioned.
An easy means of visible indication, and a way to keep the most recent setting, is the reason why I will probably go with a DC-voltage driven control. A linear potentiometer would look and behave like a regular volume control. The micro's A/D input would sample the setting.
After thinking it through, I have no need for remote volume control so probably won't add it to mine.
A question I have for every one is: how many steps for a volume control? What range in dB? Obviously 0 is no gain, and full is 0 dB, but what should the steps in the middle be?
Paul
After thinking it through, I have no need for remote volume control so probably won't add it to mine.
A question I have for every one is: how many steps for a volume control? What range in dB? Obviously 0 is no gain, and full is 0 dB, but what should the steps in the middle be?
Paul
Gene,
concerning ISP programming of AVR microcntrollers, you might have alook here:
http://www.omegav.ntnu.no/avr/resources.php3
Holger
concerning ISP programming of AVR microcntrollers, you might have alook here:
http://www.omegav.ntnu.no/avr/resources.php3
Holger
Maybee you would like this link :
http://www.avrfreaks.com
It's a forum like this.. There are free C-compilers (GCC), IDE and ASSEMBLERS.
hehe .. if you try http://www.picfreaks.com ...
It is interresting discussion ... I have recently got samples from Wolfson Microelectronics : WM8816 5 - pcs. I am going to try them out.
Sonny
http://www.avrfreaks.com
It's a forum like this.. There are free C-compilers (GCC), IDE and ASSEMBLERS.
hehe .. if you try http://www.picfreaks.com ...
It is interresting discussion ... I have recently got samples from Wolfson Microelectronics : WM8816 5 - pcs. I am going to try them out.
Sonny
new PGA2310 Eval Board Datasheet available
Just in case you haven't checked, TI/Burr Brown recently added the data sheet for the evaluation board for the PGA2310.
http://www.ti.com/sc/docs/psheets/newdocs/audio_volume_controls.html
Michael
Just in case you haven't checked, TI/Burr Brown recently added the data sheet for the evaluation board for the PGA2310.
http://www.ti.com/sc/docs/psheets/newdocs/audio_volume_controls.html
Michael
Two comments:
1. The LS7083 may help simplify the programming, but it doesn't replace a microprocessor, because the PGA2310 doesn't accept an upcount / downcount input directly. You still need a micro (unless I'm missing something). Other volume control chips like the Dallas ones have these types of inputs.
2. The Eval board for the PGA2310 interfaces it to a PC's parallel (printer) port. Your PC runs the PGA2310 the same way an embedded microcontroller would. The PC software source code is probably not available; even if it were it probably wouldn't help too much to write code for a micro because it's not probably not written in an abstract fashion that could be ported easily.
However, you could probably use this eval board directly with a small micro board - something I'd like to consider.
Does anyone know how these eval boards are ordered? Directly from TI or through a distributor?
1. The LS7083 may help simplify the programming, but it doesn't replace a microprocessor, because the PGA2310 doesn't accept an upcount / downcount input directly. You still need a micro (unless I'm missing something). Other volume control chips like the Dallas ones have these types of inputs.
2. The Eval board for the PGA2310 interfaces it to a PC's parallel (printer) port. Your PC runs the PGA2310 the same way an embedded microcontroller would. The PC software source code is probably not available; even if it were it probably wouldn't help too much to write code for a micro because it's not probably not written in an abstract fashion that could be ported easily.
However, you could probably use this eval board directly with a small micro board - something I'd like to consider.
Does anyone know how these eval boards are ordered? Directly from TI or through a distributor?
paulb,
You are correct. There is still a need to convert the parallel data into a serial format. I don’t see this as a very big problem. But it would take a few extra parts and is a good option for those that do not want to use a micro.
I have been looking into the PIC micro and have collected some software to program these. However I still don’t have the time required to learn how to use the PIC. I’m just collecting parts to explore all potential possibilities.
I now have the surface mount and through hole version of the PGA2310 on hand. I may attempt to incorporate one of these into one of my new all discrete MOSFET preamps when time allows.
I will try to find out if the evaluation board for the PGA2310 is available direct from TI. I rather suspect that they would route a request for one to one of the regional distributors. I would hesitate to purchase one since it would likely only be used for a very short period of time.
John Fassotte
Alaskan Audio
You are correct. There is still a need to convert the parallel data into a serial format. I don’t see this as a very big problem. But it would take a few extra parts and is a good option for those that do not want to use a micro.
I have been looking into the PIC micro and have collected some software to program these. However I still don’t have the time required to learn how to use the PIC. I’m just collecting parts to explore all potential possibilities.
I now have the surface mount and through hole version of the PGA2310 on hand. I may attempt to incorporate one of these into one of my new all discrete MOSFET preamps when time allows.
I will try to find out if the evaluation board for the PGA2310 is available direct from TI. I rather suspect that they would route a request for one to one of the regional distributors. I would hesitate to purchase one since it would likely only be used for a very short period of time.
John Fassotte
Alaskan Audio
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