Part Number: LM, Maunfacturer: National Semiconductor, Part Family: LM, File type: PDF, Document: Datasheet – semiconductor. The LM and LMC are general purpose tone decod- ers designed to provide a saturated transistor switch to ground when an input signal is present within. DESCRIPTION. The NE/SE tone and frequency decoder is a highly stable phase-locked loop with synchronous AM lock detection and.
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Currently I use 2. If C3 is too small, frequencies just outside the detection band will switch the output stage on and off at the beat frequency, or the output may pulse on and off during the turn-on transient.
Shockingly poor wrt applications. What equation do I use for the input and output filter capacitor for the to successfully detect a 5Khz tone? Andy aka k 10 LM used in IR controller.
The Philips data sheet makes design easy [tm]. Home Questions Tags Users Unanswered. How exactly does one calculate the proper filter capacitors for the tone detector? Link to datasheet – for the at least?
Everything is working OK with the exception of the tone detector, yet I can hear the tone when I dagasheet up a speaker to my circuit at the point where the tone detector can pick the same noise up.
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LM567 Datasheet PDF
Rl on pin 8 in the diagram below. Natsemi – looks familiar: Lots of ideas – each image links to a page.
If C3 is too large, turn-on and turn-off of the output stage will be delayed until the voltage on C3 passes the threshold voltage. Russell McMahon k 9 Sign up using Facebook. The tone I’m trying to detect is a tone at 5Khz.
LM datasheet, Pinout ,application circuits Tone Decoder – National Semiconductor
Without this the device is about as good at detecting tones as is a pillar of salt. I think it comes down to the input filter capacitor and output filter capacitor connected to the I can’t accept this answer because I’m trying to dtasheet out how to calculate values of C3 and C2.
I’m making a wireless remote control system using the and IC’s. Sign up using Email and Password. C3 sets the band edge of a low-pass filter which attenuates frequencies outside the detection band to eliminate spurious outputs. Here is an online calculator for all tone related dattasheet.
Tone Decoder – National Semiconductor
It is likely that the lack of output is due to you adtasheet having allowed for the fact that the LM has an “open collector” output. TI LM data sheet here – Detailed design requirements are given in section Output is low when tone is ‘detected’. Email Required, but never shown.
Post as a guest Name. What you and other sources online have demonstrated is how to determine the detection frequency using C1 and R1. Output filter capacitor C3 – From Philips data sheet page “The value of C3 is generally non-critical. Page contains most of what you need to know, but there is also much more there that is useful. Such delay may be desirable to avoid spurious outputs due to transient frequencies.