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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Tone Decoder – National Semiconductor

C3 sets the band edge of a low-pass filter which attenuates frequencies outside the detection band to eliminate spurious outputs. By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Rl on pin 8 in the dwtasheet below. Currently I use 2. Such delay may be desirable to avoid spurious outputs due to transient frequencies. Here is an online calculator for all tone related components.

LM datasheet, Pinout ,application circuits Tone Decoder – National Semiconductor

Sign up using Email and Password. Output filter capacitor C3 – From Philips data sheet page “The value of C3 is generally non-critical.


I can’t accept this answer because I’m trying to figure out how to calculate values of C3 and C2. I think it comes down to the input filter capacitor and output filter capacitor connected to the Natsemi – looks familiar: It is likely that the lack of output is due to you not having allowed datasgeet the fact that the LM has an “open collector” output.

TI LM data sheet here – Detailed design requirements are given in section What you and other sources online have demonstrated is how to determine the detection frequency using C1 and R1.

Everything is working OK with the exception of the tone detector, yet I can hear the tone when I hook up a speaker to my circuit at the point where the tone detector can pick the same l,567 up. Page contains most of what you need to know, but there is also much more there that is useful.

Lots of ideas – each image links to a page. Link to datasyeet – for lj567 at least? Post as a guest Name. Russell McMahon k 9 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.

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Without this the device is about as good at detecting tones as is a pillar of salt. Output is low when tone is ‘detected’. Sign up or log in Sign up using Google.

The Philips data sheet makes design easy [tm]. Andy aka k 10 What equation do I use for the input and output filter capacitor for the to successfully detect a 5Khz tone? 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 datassheet turn-on transient.

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The tone I’m trying to detect is a tone at 5Khz. LM used in IR controller.

How exactly does one calculate the proper filter capacitors for the tone detector? Email Required, but never shown. I’m making a wireless remote control system using the and IC’s. By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is datasheeet to these policies.

Shockingly poor wrt applications.