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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TI LM data sheet here – Detailed design requirements are given in section Email Required, but never shown. Sign up using Email datashest Password. Russell McMahon k 9 I think it comes down to the input filter capacitor and output filter capacitor connected to the What you llm567 other sources online have demonstrated is how to determine the detection frequency using C1 and R1.
Home Questions Tags Users Unanswered. Such delay may be desirable to avoid spurious outputs due to transient frequencies.
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 noise up. LM used in IR controller.
Tone Decoder – National Semiconductor
How exactly does one calculate the proper filter capacitors for the tone detector? Output filter capacitor C3 – From Philips data sheet page “The value of C3 is generally non-critical. Andy aka k 10 Link to datasheet – for the at least? 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.
C3 sets the band edge of a low-pass filter which attenuates frequencies outside the detection band to eliminate spurious outputs.
LM datasheet, Pinout ,application circuits Tone Decoder – National Semiconductor
The tone I’m trying to detect is a tone at 5Khz. What equation do I use for the input and output filter capacitor for the to successfully detect a 5Khz tone? Currently I use 2.
Sign up or log in Sign up using Google. The Philips data sheet makes design easy [tm].
Rl on pin 8 in the diagram below. Output is low when tone is ‘detected’. Natsemi – looks familiar: 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. Lots of ideas – each image links to a page. Without this the device is about as good at detecting tones as is a pillar of salt. It is likely that the lack of output is due to you not having allowed for the fact that the LM has an “open collector” output.
National Semiconductor – datasheet pdf
Shockingly poor wrt applications.
I can’t accept this answer because I’m trying to figure out how to calculate values of C3 and C2.