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On a sunny day (Sat, 21 Feb 2004 19:22:15 +0000) it happened Paul Burridge
wrote in : On Sat, 21 Feb 2004 18:22:44 +0000, Leon Heller wrote: Paul Burridge wrote: Anyone care to nominate an RF mixer chip for 100Mhz that's readily available in the UK? What sort of performance is required? "Good." :-) Diode mixers are easy to obtain and have good IMD characteristics. The impedances on the ports need to be properly matched. What - the sort of crossed diode config one often sees in the ham design books? Do you think I might as well just make one up from discretes? I'm basically just trying to combine 60Mhz with 20Mhz to end up with the difference frequency in this case. JJ suggested a chip, but looking at the data sheet, it seemed to be designed more as a modulator than a mixer. Let's not get into an argument over semantics but y'all know what I mean, I'm sure. BTW, thanks for a good steer with the Pulsonix suggestion, Leon. I'm making good progress getting to grips with it. I do this with a dual gate MOSFET, osc on second gate, signal on first. A voltage divider on gate 2 to set it in teh non-linear part. This works very well, is not critical, very cheap and extremely reliable. Also the noise figure is good. So tuned 40MHz in drain I did one some weeks agao, but cant remember what that was for? Anyway that sceme works up to a GHz , from kHz up. If you need diagram and part example I could draw up one here. Copyright Jan Panteltje 2004 All Right Reserved By reading this you agree to pay me 1 fc. |
Paul Burridge wrote: On Sat, 21 Feb 2004 18:22:44 +0000, Leon Heller wrote: Paul Burridge wrote: Anyone care to nominate an RF mixer chip for 100Mhz that's readily available in the UK? What sort of performance is required? "Good." :-) Diode mixers are easy to obtain and have good IMD characteristics. The impedances on the ports need to be properly matched. What - the sort of crossed diode config one often sees in the ham design books? Do you think I might as well just make one up from discretes? I'm basically just trying to combine 60Mhz with 20Mhz to end up with the difference frequency in this case. JJ suggested a chip, but looking at the data sheet, it seemed to be designed more as a modulator than a mixer. Let's not get into an argument over semantics but y'all know what I mean, I'm sure. You could make your own, but an MCL TUF-1 or SBL-1 won't be all that expensive. They do need a 7 dBm local oscillator drive level. BTW, thanks for a good steer with the Pulsonix suggestion, Leon. I'm making good progress getting to grips with it. You could join the Pulsonix UG: http://groups.yahoo.com/group/PulsonixUG/ Leon -- Leon Heller, G1HSM Email: My low-cost Philips LPC210x ARM development system: http://www.geocities.com/leon_heller/lpc2104.html |
Paul Burridge wrote: On Sat, 21 Feb 2004 18:22:44 +0000, Leon Heller wrote: Paul Burridge wrote: Anyone care to nominate an RF mixer chip for 100Mhz that's readily available in the UK? What sort of performance is required? "Good." :-) Diode mixers are easy to obtain and have good IMD characteristics. The impedances on the ports need to be properly matched. What - the sort of crossed diode config one often sees in the ham design books? Do you think I might as well just make one up from discretes? I'm basically just trying to combine 60Mhz with 20Mhz to end up with the difference frequency in this case. JJ suggested a chip, but looking at the data sheet, it seemed to be designed more as a modulator than a mixer. Let's not get into an argument over semantics but y'all know what I mean, I'm sure. You could make your own, but an MCL TUF-1 or SBL-1 won't be all that expensive. They do need a 7 dBm local oscillator drive level. BTW, thanks for a good steer with the Pulsonix suggestion, Leon. I'm making good progress getting to grips with it. You could join the Pulsonix UG: http://groups.yahoo.com/group/PulsonixUG/ Leon -- Leon Heller, G1HSM Email: My low-cost Philips LPC210x ARM development system: http://www.geocities.com/leon_heller/lpc2104.html |
On Sat, 21 Feb 2004 12:28:13 +0000, Paul Burridge
wrote: Anyone care to nominate an RF mixer chip for 100Mhz that's readily available in the UK? Since you don't specify anything important like IP3, my recommendation is Siemens S042P. Earlier, when Motorola was easy to buy from, I would have used MC1496P, but none of them have high IP3 and I suppose NE602 isn't any better. If balance isn't important, I would use BF905 or BF199 73, LA8AK http://home.online.no/~la8ak/ ---- Jan-Martin, LA8AK, N-4623 Kristiansand http://home.online.no/~la8ak/ |
On Sat, 21 Feb 2004 12:28:13 +0000, Paul Burridge
wrote: Anyone care to nominate an RF mixer chip for 100Mhz that's readily available in the UK? Since you don't specify anything important like IP3, my recommendation is Siemens S042P. Earlier, when Motorola was easy to buy from, I would have used MC1496P, but none of them have high IP3 and I suppose NE602 isn't any better. If balance isn't important, I would use BF905 or BF199 73, LA8AK http://home.online.no/~la8ak/ ---- Jan-Martin, LA8AK, N-4623 Kristiansand http://home.online.no/~la8ak/ |
On Sun, 22 Feb 2004 06:41:10 +0000, Leon Heller
wrote: You could make your own, but an MCL TUF-1 or SBL-1 won't be all that expensive. They do need a 7 dBm local oscillator drive level. Thanks. I'll check 'em out. You could join the Pulsonix UG: http://groups.yahoo.com/group/PulsonixUG/ Will do. There are a couple of minor queries that have arisen. -- The BBC: Licensed at public expense to spread lies. |
On Sun, 22 Feb 2004 06:41:10 +0000, Leon Heller
wrote: You could make your own, but an MCL TUF-1 or SBL-1 won't be all that expensive. They do need a 7 dBm local oscillator drive level. Thanks. I'll check 'em out. You could join the Pulsonix UG: http://groups.yahoo.com/group/PulsonixUG/ Will do. There are a couple of minor queries that have arisen. -- The BBC: Licensed at public expense to spread lies. |
Do the dual gate mosfets outperform the NE602 with regards to IP3?
For some reason the NE602 refuses to oscillate with crystals but LC's are OK. Since you don't specify anything important like IP3, my recommendation is Siemens S042P. Earlier, when Motorola was easy to buy from, I would have used MC1496P, but none of them have high IP3 and I suppose NE602 isn't any better. If balance isn't important, I would use BF905 or BF199 73, LA8AK http://home.online.no/~la8ak/ ---- Jan-Martin, LA8AK, N-4623 Kristiansand http://home.online.no/~la8ak/ |
Do the dual gate mosfets outperform the NE602 with regards to IP3?
For some reason the NE602 refuses to oscillate with crystals but LC's are OK. Since you don't specify anything important like IP3, my recommendation is Siemens S042P. Earlier, when Motorola was easy to buy from, I would have used MC1496P, but none of them have high IP3 and I suppose NE602 isn't any better. If balance isn't important, I would use BF905 or BF199 73, LA8AK http://home.online.no/~la8ak/ ---- Jan-Martin, LA8AK, N-4623 Kristiansand http://home.online.no/~la8ak/ |
On Sun, 22 Feb 2004 18:09:03 -0000, SWbeginner
wrote: Do the dual gate mosfets outperform the NE602 with regards to IP3? For some reason the NE602 refuses to oscillate with crystals but LC's are OK. [snip] The NE602 only supports Colpitts and Butler crystal oscillator configurations. It is *not* an inverter-style oscillator. See: http://www.semiconductors.com/acroba...tes/AN1983.pdf ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
On Sun, 22 Feb 2004 18:09:03 -0000, SWbeginner
wrote: Do the dual gate mosfets outperform the NE602 with regards to IP3? For some reason the NE602 refuses to oscillate with crystals but LC's are OK. [snip] The NE602 only supports Colpitts and Butler crystal oscillator configurations. It is *not* an inverter-style oscillator. See: http://www.semiconductors.com/acroba...tes/AN1983.pdf ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
On Sun, 22 Feb 2004 18:09:03 -0000, SWbeginner
wrote: Do the dual gate mosfets outperform the NE602 with regards to IP3? For some reason the NE602 refuses to oscillate with crystals but LC's are OK. Since you don't specify anything important like IP3, my recommendation is Siemens S042P. Earlier, when Motorola was easy to buy from, I would have used MC1496P, but none of them have high IP3 and I suppose NE602 isn't any better. If balance isn't important, I would use BF905 or BF199 ---- Jan-Martin, LA8AK, N-4623 Kristiansand technical topics http://home.online.no/~la8ak/c.htm here is the first mention of IP3 in the thread, I've asked whether it is important or not, but have not received any confirmation and will therefore not comment. If IP3 was said to be important I am aware of other mixers, and have used some douzens SBL1, SBL-1X, CM-1, SRA1 and other since 1977. A very easy mixer to use is TBA120=SN76660N. I usually construct to requirement, not what somebody else think is fine 73 ---- Jan-Martin, LA8AK, N-4623 Kristiansand http://home.online.no/~la8ak/ |
On Sun, 22 Feb 2004 18:09:03 -0000, SWbeginner
wrote: Do the dual gate mosfets outperform the NE602 with regards to IP3? For some reason the NE602 refuses to oscillate with crystals but LC's are OK. Since you don't specify anything important like IP3, my recommendation is Siemens S042P. Earlier, when Motorola was easy to buy from, I would have used MC1496P, but none of them have high IP3 and I suppose NE602 isn't any better. If balance isn't important, I would use BF905 or BF199 ---- Jan-Martin, LA8AK, N-4623 Kristiansand technical topics http://home.online.no/~la8ak/c.htm here is the first mention of IP3 in the thread, I've asked whether it is important or not, but have not received any confirmation and will therefore not comment. If IP3 was said to be important I am aware of other mixers, and have used some douzens SBL1, SBL-1X, CM-1, SRA1 and other since 1977. A very easy mixer to use is TBA120=SN76660N. I usually construct to requirement, not what somebody else think is fine 73 ---- Jan-Martin, LA8AK, N-4623 Kristiansand http://home.online.no/~la8ak/ |
On Mon, 23 Feb 2004 16:01:50 +0100, "Jan-Martin Noeding, LA8AK"
wrote: here is the first mention of IP3 in the thread, I've asked whether it is important or not, but have not received any confirmation and will therefore not comment. If IP3 was said to be important I am aware of other mixers, and have used some douzens SBL1, SBL-1X, CM-1, SRA1 and other since 1977. A very easy mixer to use is TBA120=SN76660N. If you have a very high-Q tunable front end filter, you usually get away with a mediocre IP3. However, if wide open (1 octave) front end filters are used, you would benefit from a high IP3 if you are using a decent antenna. If you try to receive the 7000 .. 7100 kHz amateur band in Europe, with 100-500 kW broadcast transmitters every 5 kHz starting at 7105 kHz, the input IP3 number would have to be at least 20 dB higher than the strongest broadcast signals or even 30 dB higher if you try to receive QRP stations. Attenuating the whole antenna signal with a passive attenuator will also rapidly drop the IP3 products, but sooner or later the weak desired signal will be lost in attenuator thermal noise. Paul OH3LWR |
On Mon, 23 Feb 2004 16:01:50 +0100, "Jan-Martin Noeding, LA8AK"
wrote: here is the first mention of IP3 in the thread, I've asked whether it is important or not, but have not received any confirmation and will therefore not comment. If IP3 was said to be important I am aware of other mixers, and have used some douzens SBL1, SBL-1X, CM-1, SRA1 and other since 1977. A very easy mixer to use is TBA120=SN76660N. If you have a very high-Q tunable front end filter, you usually get away with a mediocre IP3. However, if wide open (1 octave) front end filters are used, you would benefit from a high IP3 if you are using a decent antenna. If you try to receive the 7000 .. 7100 kHz amateur band in Europe, with 100-500 kW broadcast transmitters every 5 kHz starting at 7105 kHz, the input IP3 number would have to be at least 20 dB higher than the strongest broadcast signals or even 30 dB higher if you try to receive QRP stations. Attenuating the whole antenna signal with a passive attenuator will also rapidly drop the IP3 products, but sooner or later the weak desired signal will be lost in attenuator thermal noise. Paul OH3LWR |
On Sun, 22 Feb 2004 18:09:03 -0000, SWbeginner
wrote: Do the dual gate mosfets outperform the NE602 with regards to IP3? For some reason the NE602 refuses to oscillate with crystals but LC's are OK. Since you don't specify anything important like IP3, Can someone kindly confirm what the hell "IP3" is?? I can only think of "3rd order intermodulation products" which might easily be completely wrong. It would be helpful if whoever first uses an uncommon abbreviation would have the courtesy to state what it meant! (as is customary first time around) snarl, hiss, etc -- The BBC: Licensed at public expense to spread lies. |
On Sun, 22 Feb 2004 18:09:03 -0000, SWbeginner
wrote: Do the dual gate mosfets outperform the NE602 with regards to IP3? For some reason the NE602 refuses to oscillate with crystals but LC's are OK. Since you don't specify anything important like IP3, Can someone kindly confirm what the hell "IP3" is?? I can only think of "3rd order intermodulation products" which might easily be completely wrong. It would be helpful if whoever first uses an uncommon abbreviation would have the courtesy to state what it meant! (as is customary first time around) snarl, hiss, etc -- The BBC: Licensed at public expense to spread lies. |
On Mon, 23 Feb 2004 23:11:27 +0000, Paul Burridge
wrote: On Sun, 22 Feb 2004 18:09:03 -0000, SWbeginner wrote: Do the dual gate mosfets outperform the NE602 with regards to IP3? For some reason the NE602 refuses to oscillate with crystals but LC's are OK. Since you don't specify anything important like IP3, Can someone kindly confirm what the hell "IP3" is?? I can only think of "3rd order intermodulation products" which might easily be completely wrong. It would be helpful if whoever first uses an uncommon abbreviation would have the courtesy to state what it meant! (as is customary first time around) snarl, hiss, etc It's only an "uncommon abbreviation" to certain Brits who think they can learn by insulting the masters ;-) Look up 3rd order intercept point. ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
On Mon, 23 Feb 2004 23:11:27 +0000, Paul Burridge
wrote: On Sun, 22 Feb 2004 18:09:03 -0000, SWbeginner wrote: Do the dual gate mosfets outperform the NE602 with regards to IP3? For some reason the NE602 refuses to oscillate with crystals but LC's are OK. Since you don't specify anything important like IP3, Can someone kindly confirm what the hell "IP3" is?? I can only think of "3rd order intermodulation products" which might easily be completely wrong. It would be helpful if whoever first uses an uncommon abbreviation would have the courtesy to state what it meant! (as is customary first time around) snarl, hiss, etc It's only an "uncommon abbreviation" to certain Brits who think they can learn by insulting the masters ;-) Look up 3rd order intercept point. ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
Paul Burridge wrote:
Can someone kindly confirm what the hell "IP3" is?? I can only think of "3rd order intermodulation products" which might easily be completely wrong. It would be helpful if whoever first uses an uncommon abbreviation would have the courtesy to state what it meant! (as is customary first time around) snarl, hiss, etc I agree it's discourteous to use an uncommon abbreviation without explanation. But IP3 is a very common abbreviation when discussing mixer or receiver performance, and it's reasonable to assume that anyone more than superficially involved in receiver or mixer design or application has at least heard the term. Or that they can at least do a simple google search. (It really doesn't take any more time than making an angry newgroup posting!) A google search of "IP3 mixers" brought about 2500 hits. I'm sure that if you read one or two of them, you'll get the idea. Roy Lewallen, W7EL |
Paul Burridge wrote:
Can someone kindly confirm what the hell "IP3" is?? I can only think of "3rd order intermodulation products" which might easily be completely wrong. It would be helpful if whoever first uses an uncommon abbreviation would have the courtesy to state what it meant! (as is customary first time around) snarl, hiss, etc I agree it's discourteous to use an uncommon abbreviation without explanation. But IP3 is a very common abbreviation when discussing mixer or receiver performance, and it's reasonable to assume that anyone more than superficially involved in receiver or mixer design or application has at least heard the term. Or that they can at least do a simple google search. (It really doesn't take any more time than making an angry newgroup posting!) A google search of "IP3 mixers" brought about 2500 hits. I'm sure that if you read one or two of them, you'll get the idea. Roy Lewallen, W7EL |
On Mon, 23 Feb 2004 21:12:44 +0200, Paul Keinanen
wrote: If you have a very high-Q tunable front end filter, you usually get away with a mediocre IP3. However, if wide open (1 octave) front end filters are used, you would benefit from a high IP3 if you are using a decent antenna. If you try to receive the 7000 .. 7100 kHz amateur band in Europe, with 100-500 kW broadcast transmitters every 5 kHz starting at 7105 kHz, the input IP3 number would have to be at least 20 dB higher than the strongest broadcast signals or even 30 dB higher if you try to receive QRP stations. Attenuating the whole antenna signal with a passive attenuator will also rapidly drop the IP3 products, but sooner or later the weak desired signal will be lost in attenuator thermal noise. Paul OH3LWR for 40m band even an SBL1 may be found inadequate and the solution is - as you say - a high-Q input selectivity using a 7040kHz ceramic filter which passes 7,0-7.1MHz within -6dB bandwidth. I've been told that my FT-902 with schottky ring mixer is worse than FT-901 with DG-mosfet 1st mixer, but I have no idea what is the main problem. I tested a mosfet mixer on 136kHz and found it adequate in most respects apart from IF leakage, and ended up with 74HC4066 mixer - used more for reason of being curious about it than that it was really needed, see http://home.online.no/~la8ak/L1.htm , but it couldn't be used on 60MHz as the orignal request was for, it might work on 40M with HEF4013 LO divider on +10VDC. Again you are fed with lot of crop from persons who don't understand the difference between what is optimum and what it the most expensive, so I expect somebody to telll me the nonsense of using FST3125 instead of 74HC4066 without understanding that the latter has almost 6dB higher IP3, and it is more fun to use an inexpensive device in spite of having the house filled up with lot of other better and expensive devices you won't have time to use in a lifetime. 73 JM ---- Jan-Martin, LA8AK, N-4623 Kristiansand http://home.online.no/~la8ak/ |
On Mon, 23 Feb 2004 21:12:44 +0200, Paul Keinanen
wrote: If you have a very high-Q tunable front end filter, you usually get away with a mediocre IP3. However, if wide open (1 octave) front end filters are used, you would benefit from a high IP3 if you are using a decent antenna. If you try to receive the 7000 .. 7100 kHz amateur band in Europe, with 100-500 kW broadcast transmitters every 5 kHz starting at 7105 kHz, the input IP3 number would have to be at least 20 dB higher than the strongest broadcast signals or even 30 dB higher if you try to receive QRP stations. Attenuating the whole antenna signal with a passive attenuator will also rapidly drop the IP3 products, but sooner or later the weak desired signal will be lost in attenuator thermal noise. Paul OH3LWR for 40m band even an SBL1 may be found inadequate and the solution is - as you say - a high-Q input selectivity using a 7040kHz ceramic filter which passes 7,0-7.1MHz within -6dB bandwidth. I've been told that my FT-902 with schottky ring mixer is worse than FT-901 with DG-mosfet 1st mixer, but I have no idea what is the main problem. I tested a mosfet mixer on 136kHz and found it adequate in most respects apart from IF leakage, and ended up with 74HC4066 mixer - used more for reason of being curious about it than that it was really needed, see http://home.online.no/~la8ak/L1.htm , but it couldn't be used on 60MHz as the orignal request was for, it might work on 40M with HEF4013 LO divider on +10VDC. Again you are fed with lot of crop from persons who don't understand the difference between what is optimum and what it the most expensive, so I expect somebody to telll me the nonsense of using FST3125 instead of 74HC4066 without understanding that the latter has almost 6dB higher IP3, and it is more fun to use an inexpensive device in spite of having the house filled up with lot of other better and expensive devices you won't have time to use in a lifetime. 73 JM ---- Jan-Martin, LA8AK, N-4623 Kristiansand http://home.online.no/~la8ak/ |
On Mon, 23 Feb 2004 16:12:55 -0700, Jim Thompson
wrote: It's only an "uncommon abbreviation" to certain Brits who think they can learn by insulting the masters ;-) Look up 3rd order intercept point. ...Jim Thompson thought everybody had studied Ham Radio December 77 throughly - even in UK..... 73 ex-G5BFV (at BPO radio station Bearley/SOA) ---- Jan-Martin, LA8AK, N-4623 Kristiansand http://home.online.no/~la8ak/ |
On Mon, 23 Feb 2004 16:12:55 -0700, Jim Thompson
wrote: It's only an "uncommon abbreviation" to certain Brits who think they can learn by insulting the masters ;-) Look up 3rd order intercept point. ...Jim Thompson thought everybody had studied Ham Radio December 77 throughly - even in UK..... 73 ex-G5BFV (at BPO radio station Bearley/SOA) ---- Jan-Martin, LA8AK, N-4623 Kristiansand http://home.online.no/~la8ak/ |
In article , Paul Burridge
writes: Since you don't specify anything important like IP3, Can someone kindly confirm what the hell "IP3" is?? I can only think of "3rd order intermodulation products" which might easily be completely wrong. It would be helpful if whoever first uses an uncommon abbreviation would have the courtesy to state what it meant! (as is customary first time around) snarl, hiss, etc Heh heh heh, can't say I blame you for being a bit confused. The "3rd Order" label is due to the mix products of F_a +/- 2F_b with F_b being twice its original frequency. "Order" comes from the constant multipliers, 1 for F_a and 2 for F_b so "1" + "2" equals 3 or the 3rd Order. What happens is that the slope of the "3rd Order" mix product is steeper than the normal F_a +/- F_b (order of 2) equation's power slope. The "3rd Order Intercept Point" is where the two slopes intersect. It is much much easier to show this graphically than in words. The reason for defining intermodulation distortion that way is in that it is simpler and more accurate to test on both the production line and in any test lab of a finished product. The old way had been to just increase the input level and VERY carefully note the output level, especially when the output level slope departed from a straight line (indicating some compression, the start of intermodulation distortion). That old system being very prone to instrument calibration errors led to some arguments between makers and buyers, not to mention non-standard notations of "1 db points" and "3 db points" of distortion relative to input levels. The Mini-Circuits website used to have some mention of the above plus the Avantek website and, of course, Agilent when the T&M division was the original Hewlett-Packard. You might find something on a search for "3rd Order IP" on the 'net that will also have graphs. Len Anderson retired (from regular hours) electronic engineering person |
In article , Paul Burridge
writes: Since you don't specify anything important like IP3, Can someone kindly confirm what the hell "IP3" is?? I can only think of "3rd order intermodulation products" which might easily be completely wrong. It would be helpful if whoever first uses an uncommon abbreviation would have the courtesy to state what it meant! (as is customary first time around) snarl, hiss, etc Heh heh heh, can't say I blame you for being a bit confused. The "3rd Order" label is due to the mix products of F_a +/- 2F_b with F_b being twice its original frequency. "Order" comes from the constant multipliers, 1 for F_a and 2 for F_b so "1" + "2" equals 3 or the 3rd Order. What happens is that the slope of the "3rd Order" mix product is steeper than the normal F_a +/- F_b (order of 2) equation's power slope. The "3rd Order Intercept Point" is where the two slopes intersect. It is much much easier to show this graphically than in words. The reason for defining intermodulation distortion that way is in that it is simpler and more accurate to test on both the production line and in any test lab of a finished product. The old way had been to just increase the input level and VERY carefully note the output level, especially when the output level slope departed from a straight line (indicating some compression, the start of intermodulation distortion). That old system being very prone to instrument calibration errors led to some arguments between makers and buyers, not to mention non-standard notations of "1 db points" and "3 db points" of distortion relative to input levels. The Mini-Circuits website used to have some mention of the above plus the Avantek website and, of course, Agilent when the T&M division was the original Hewlett-Packard. You might find something on a search for "3rd Order IP" on the 'net that will also have graphs. Len Anderson retired (from regular hours) electronic engineering person |
By the way, the topic of third order intercept point is covered very
nicely in _Experimental Methods in RF Design_. As in its predecessor _Solid State Design for the Radio Amateur_ (Hayward and DeMaw), the authors point out that it's not always obvious whether the intercept is at a circuit's input or output, and consequently the importance of specifying which is meant. So in that book, you'll also find the more obscure but unambiguous abbreviations IIP3 and OIP3. Roy Lewallen, W7EL |
By the way, the topic of third order intercept point is covered very
nicely in _Experimental Methods in RF Design_. As in its predecessor _Solid State Design for the Radio Amateur_ (Hayward and DeMaw), the authors point out that it's not always obvious whether the intercept is at a circuit's input or output, and consequently the importance of specifying which is meant. So in that book, you'll also find the more obscure but unambiguous abbreviations IIP3 and OIP3. Roy Lewallen, W7EL |
On Mon, 23 Feb 2004 16:12:55 -0700, Jim Thompson
wrote: Look up 3rd order intercept point. And pay special attention if this is input IP3 (the power of the test tones are measured at the input of the device) or output IP3 (power levels measured at device output). This is especially important, since a typical active Gilbert cell mixer (1496, NE602) have some gain, while a typical diode ring mixer (SBL-1) have a 6-7 dB loss. Paul OH3LWR |
On Mon, 23 Feb 2004 16:12:55 -0700, Jim Thompson
wrote: Look up 3rd order intercept point. And pay special attention if this is input IP3 (the power of the test tones are measured at the input of the device) or output IP3 (power levels measured at device output). This is especially important, since a typical active Gilbert cell mixer (1496, NE602) have some gain, while a typical diode ring mixer (SBL-1) have a 6-7 dB loss. Paul OH3LWR |
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Jan-Martin Noeding, LA8AK wrote in message ... On Mon, 23 Feb 2004 16:12:55 -0700, Jim Thompson wrote: It's only an "uncommon abbreviation" to certain Brits who think they can learn by insulting the masters ;-) Look up 3rd order intercept point. ...Jim Thompson thought everybody had studied Ham Radio December 77 throughly - even in UK..... 73 ex-G5BFV (at BPO radio station Bearley/SOA) ---- Jan-Martin, LA8AK, N-4623 Kristiansand http://home.online.no/~la8ak/ That's a helluva web site you keep there :-) Impressive! regards john |
Jan-Martin Noeding, LA8AK wrote in message ... On Mon, 23 Feb 2004 16:12:55 -0700, Jim Thompson wrote: It's only an "uncommon abbreviation" to certain Brits who think they can learn by insulting the masters ;-) Look up 3rd order intercept point. ...Jim Thompson thought everybody had studied Ham Radio December 77 throughly - even in UK..... 73 ex-G5BFV (at BPO radio station Bearley/SOA) ---- Jan-Martin, LA8AK, N-4623 Kristiansand http://home.online.no/~la8ak/ That's a helluva web site you keep there :-) Impressive! regards john |
"W3JDR" wrote in message ... Take a look at Analog Devices' line of DDS chips. Pretty much a one-chip (needs ucontroller to drive it) digital solution to turn your 10MHz clock into virtually any frequency below 5 MHz (in theory; below 4MHz in easy practicality). The AD9834 only consumes 20mw at 3.3 VDC. There are many other devices in the product line. Many have built-in comparators to produce square-wave output. Joe W3JDR Joe, I'd gladly use the Analog Devices DDS chips if they offered them in something other than a SadoMasochistic Device (SMD) package. It's a darn shame they can't make a limited run (say 10k) of some of these chips in a PDIP package for hams and other r.f. experimenters. If they put the AD9835 in a PDIP and sold it for about $10.00 (the TSSOP packaged version sells for about $6, I think) , I'd buy a dozen for various projects, but in the tiny SMD package they're nothing but useless to me. I'm new to the newsgroup and am sure that this is not the first gripe about SMD's, but I refuse to use them - not because I can't (at least not yet), but because I don't want to endure the angst. -- Chip KC5UES real E-mail Address: -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
"W3JDR" wrote in message ... Take a look at Analog Devices' line of DDS chips. Pretty much a one-chip (needs ucontroller to drive it) digital solution to turn your 10MHz clock into virtually any frequency below 5 MHz (in theory; below 4MHz in easy practicality). The AD9834 only consumes 20mw at 3.3 VDC. There are many other devices in the product line. Many have built-in comparators to produce square-wave output. Joe W3JDR Joe, I'd gladly use the Analog Devices DDS chips if they offered them in something other than a SadoMasochistic Device (SMD) package. It's a darn shame they can't make a limited run (say 10k) of some of these chips in a PDIP package for hams and other r.f. experimenters. If they put the AD9835 in a PDIP and sold it for about $10.00 (the TSSOP packaged version sells for about $6, I think) , I'd buy a dozen for various projects, but in the tiny SMD package they're nothing but useless to me. I'm new to the newsgroup and am sure that this is not the first gripe about SMD's, but I refuse to use them - not because I can't (at least not yet), but because I don't want to endure the angst. -- Chip KC5UES real E-mail Address: -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
If they put the AD9835 in a PDIP and sold it for about $10.00 (the TSSOP
packaged version sells for about $6, I think) , I'd buy a dozen for various projects, but in the tiny SMD package they're nothing but useless to me. I'm new to the newsgroup and am sure that this is not the first gripe about SMD's, but I refuse to use them - not because I can't (at least not yet), but because I don't want to endure the angst. Sounds like a good opportunity for an enterprising ham - fab up a bunch of adapter boards (or buy 'em premade - I think Ares has something like this), solder down the SMD parts, and sell the resulting PDIP-compatible boards to interested homebrewers. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
If they put the AD9835 in a PDIP and sold it for about $10.00 (the TSSOP
packaged version sells for about $6, I think) , I'd buy a dozen for various projects, but in the tiny SMD package they're nothing but useless to me. I'm new to the newsgroup and am sure that this is not the first gripe about SMD's, but I refuse to use them - not because I can't (at least not yet), but because I don't want to endure the angst. Sounds like a good opportunity for an enterprising ham - fab up a bunch of adapter boards (or buy 'em premade - I think Ares has something like this), solder down the SMD parts, and sell the resulting PDIP-compatible boards to interested homebrewers. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
Chip,
I totally agree with you about the difficulty in handling fine-pitch SMD parts. It's a sign of the times. FYI, check out the DDS Daughterboard at www.njqrp.org. This is a DDS application board kit with on-board clock oscillator (you could run it from an external oscillator if you wish). There's also a link to a service that will solder your DDS chip to your bare board for $6 in single quantities. Joe W3JDR "ChipS" wrote in message ... "W3JDR" wrote in message ... Take a look at Analog Devices' line of DDS chips. Pretty much a one-chip (needs ucontroller to drive it) digital solution to turn your 10MHz clock into virtually any frequency below 5 MHz (in theory; below 4MHz in easy practicality). The AD9834 only consumes 20mw at 3.3 VDC. There are many other devices in the product line. Many have built-in comparators to produce square-wave output. Joe W3JDR Joe, I'd gladly use the Analog Devices DDS chips if they offered them in something other than a SadoMasochistic Device (SMD) package. It's a darn shame they can't make a limited run (say 10k) of some of these chips in a PDIP package for hams and other r.f. experimenters. If they put the AD9835 in a PDIP and sold it for about $10.00 (the TSSOP packaged version sells for about $6, I think) , I'd buy a dozen for various projects, but in the tiny SMD package they're nothing but useless to me. I'm new to the newsgroup and am sure that this is not the first gripe about SMD's, but I refuse to use them - not because I can't (at least not yet), but because I don't want to endure the angst. -- Chip KC5UES real E-mail Address: -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
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