| ??? 10/15/08 11:04 Read: times |
#159076 - Notes Responding to: ???'s previous message |
Richard Erlacher said:
Isn't spectral purity an issue in cases such as this? Its not that essential, if you use synchronous rectifiers. A good looking sine wave is sufficient. You mention drift ... Does that mean that the DDS+LVDT pair would occasionally need the attention of a technician, as it ages, or can its drift be handled with firmware? They don't really age WRT frequency of operation. ... how close to the desired frequency can one actually get with a given DDS chip? Since we are only after a maximum of high acoustic frequencies, you can underclock the DDS. That way you can get milli-hertz resolution. Steve |
| Topic | Author | Date |
| Function Generator IC | 01/01/70 00:00 | |
| Better? | 01/01/70 00:00 | |
| Maxim | 01/01/70 00:00 | |
| Maxim unavailable | 01/01/70 00:00 | |
| DDS? | 01/01/70 00:00 | |
| Better? .5% -1% THD with discrete solution? | 01/01/70 00:00 | |
| Wein bridge? | 01/01/70 00:00 | |
| Simple wont do ... | 01/01/70 00:00 | |
| LVDT driving | 01/01/70 00:00 | |
| High performance can be simple | 01/01/70 00:00 | |
| Tuning | 01/01/70 00:00 | |
| DDS again | 01/01/70 00:00 | |
| Design. | 01/01/70 00:00 | |
| What frequency? | 01/01/70 00:00 | |
| frequency | 01/01/70 00:00 | |
| Err | 01/01/70 00:00 | |
| DDS again | 01/01/70 00:00 | |
| THD | 01/01/70 00:00 | |
| THD | 01/01/70 00:00 | |
| reference | 01/01/70 00:00 | |
| Yes, but at what cost? | 01/01/70 00:00 | |
| About 4 bucks | 01/01/70 00:00 | |
| Better? In what way? | 01/01/70 00:00 | |
| 6 dollars | 01/01/70 00:00 | |
| Gee ... That isn't so bad! | 01/01/70 00:00 | |
| Tuning | 01/01/70 00:00 | |
| Hand-tuning is not cheap! | 01/01/70 00:00 | |
| Drift | 01/01/70 00:00 | |
| how does drift impact the manpower requirement? | 01/01/70 00:00 | |
| Notes | 01/01/70 00:00 | |
| Amplitude , tempco | 01/01/70 00:00 | |
| Precision | 01/01/70 00:00 | |
| Precision ... | 01/01/70 00:00 | |
| at that rate | 01/01/70 00:00 | |
| to Steve | 01/01/70 00:00 | |
| LVDT | 01/01/70 00:00 | |
| power/energy meter IC | 01/01/70 00:00 | |
energy meter IC | 01/01/70 00:00 | |
| at that rate | 01/01/70 00:00 | |
| Filtering? | 01/01/70 00:00 | |
| It will remove SOME of the distortion | 01/01/70 00:00 | |
| have you seen this? | 01/01/70 00:00 | |
| I am afraid | 01/01/70 00:00 | |
| Simple` | 01/01/70 00:00 | |
| DTMF Genarator | 01/01/70 00:00 |