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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National Semiconductor – datasheet pdf
LM datasheet, Pinout ,application circuits Tone Decoder – National Semiconductor
Currently I use 2. Rl on pin 8 in the diagram below. Output is low satasheet tone is ‘detected’. What equation do I use for the input and output filter capacitor for the to successfully detect a 5Khz tone? Natsemi – looks familiar: 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.
It is likely that the lack of output is due to you not having allowed for dxtasheet fact that the LM has an “open collector” output. Post as a guest Name. Page contains most of what you need to know, but there is also much more there that is useful.
LM567 Datasheet PDF
Here is an online calculator for all tone related components. Link to datasheet – for the at least? Such delay may be desirable to avoid spurious outputs due to transient frequencies. Email Required, but never shown.
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. LM used in IR controller.
Without this the device is about as good at detecting tones as is a pillar of salt. Lots of ideas – each image links to a page.
C3 sets the band edge of a low-pass filter which attenuates frequencies outside the detection band to eliminate spurious outputs. Sign up using Email and Password. How exactly does one calculate the proper filter capacitors for the tone detector? Russell McMahon k 9 I think it comes down to the input filter capacitor and output filter capacitor connected to the Andy aka k 10 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.
Sign up or log in Sign up using Google. What you and other sources online have demonstrated is how to determine the detection frequency using C1 and R1.
The Philips data sheet makes design easy [tm]. TI LM data sheet here – Detailed design requirements are given in section Shockingly poor wrt applications.