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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Andy aka k 10 What equation do I use for the input and output filter capacitor for the to successfully detect a 5Khz tone? What you and other sources online have demonstrated is how to determine the detection frequency using C1 and R1.
LM datasheet, Pinout ,application circuits Tone Decoder – National Semiconductor
Such delay may be vatasheet to avoid spurious outputs due to transient frequencies. Russell McMahon k 9 I’m making a wireless remote control system using the and IC’s. Home Questions Tags Users Unanswered. Email Required, but never shown.
I think it comes down to the input filter capacitor and output filter capacitor connected to the Shockingly poor wrt applications.
Without this the device is about as good at detecting tones as is a pillar of salt. Here is an online calculator for all tone related components.
The tone I’m trying to detect is a tone at 5Khz. How exactly does one calculate the proper filter capacitors for the tone detector?
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. C3 sets the band edge of a low-pass filter which attenuates frequencies outside the detection band to eliminate spurious outputs.
National Semiconductor – datasheet pdf
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 ddatasheet up. Currently I use 2.
Rl on pin 8 in the diagram below. 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. Natsemi – looks familiar: Output is low when tone is ‘detected’.
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” datasyeet. Sign up using Email and Password. Sign up or log in Sign up using Google.
Page contains most of what you need to know, but there is also much more there that is useful.
LM used in IR controller. The Philips data sheet makes design easy [tm]. I can’t accept this answer because I’m trying to figure out how to calculate values of C3 and C2. TI LM data sheet here – Detailed design requirements are given in section Sign up using Facebook. Output filter capacitor C3 – From Philips data sheet page “The value of C3 is generally non-critical.