An additional control input allows loudness compensation to be simply effected. Four control inputs provide control of the bass, treble, balance and volume functions through application of DC voltages from a remote control system or, alternatively, from four potentiometers which may be biased from a zener regulated supply provided on the circuit. Each tone response is defined by a single capacitor chosen to give the desired characteristic. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits.
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An additional control input allows loudness compensation to be simply effected. Four control inputs provide control of the bass, treble, balance and volume functions through application of DC voltages from a remote control system or, alternatively, from four potentiometers which may be biased from a zener regulated supply provided on the circuit.
Each tone response is defined by a single capacitor chosen to give the desired characteristic. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits.
See Application Notes. Note 3: The tone control range is defined by capacitors Cb and Ct. Note 4: Gaussian noise, measured over a period of 50 ms per channel, with a CCIR filter referenced to 2 kHz and an average-responding meter. For the values of Cb and Ct of 0. Setting a DC level of one half of the zener voltage on the control inputs, pins 4, 9, and 14, results in the balanced gain and flat response condition. If this is the case, then they will need to be derived with similar accuracy.
This operates on the tone control stages to produce an additional boost limited by the maximum boost defined by Cb and Ct. There is no loudness compensation when pin 7 is connected to pin Pin 7 can be connected to pin 12 to give the loudness compensated volume characteristic as illustrated without the addition of further external components.
Tone settings are for flat response, Cb and Ct as given in Application Circuit. Modification to the loudness characteristic is possible by changing the capacitors Cb and Ct for a different basic response or, by a resistor network between pins 7 and 12 for a different threshold and slope.
The first stage is before the tone control processing and provides an initial 15 dB of gain reduction, so ensuring that the tone sections are not overdriven by large input levels when operating with a low volume setting. As there is volume control on the input stages, the inputs may be operated with a lower overload margin than would otherwise be acceptable, allowing a possible improvement in signal to noise ratio.
In the various applications where the LM can be used, there may be requirements for responses different to those of the standard application circuit given in the data sheet. This application section details some of the simple variations possible on the standard responses, to assist the choice of optimum characteristics for particular applications.
Figure 1 shows the typical tone response obtained in the standard application circuit. Response curves are given for various amounts of boost and cut.
The values of the bypass capacitors may become significant and affect the lower frequencies in the bass response curves. The various results corresponding to the different Ct and Cb values may be mixed if it is required to give a particular emphasis to, for example, the bass control.
Restriction of Tone Control Action at High or Low Frequencies It may be desired in some applications to level off the tone responses above or below certain frequencies for example to reduce high frequence noise.
This may be achieved for the treble response by including a resistor in series with Ct. A similar effect may be obtained for the bass response by reducing the value of the AC bypass capacitors on pins 5 channel 1 and 16 channel 2. The internal resistance at these pins is 1. An example of such modified response curves is shown in Figure 6. The input coupling capacitors may also modify the low frequency response.
It will be seen from Figure 2 and Figure 3 that modifying Ct and Cb for greater control range also has the effect of flattening the tone control extremes and this may be utilized, with or without additional modification as outlined above, for the most suitable tone control range and response shape. For example, the negative-going peaks of the output amplifiers may be detected below a certain level, and used to bias back the bass control from a high boost condition, to prevent overloading the speaker with low frequency components.
There is normally 1 dB more bass than treble boost 40 Hz—16 kHz with loudness control in the standard circuit. If a greater difference is desired, it is necessary to introduce an offset by means of Ct or Cb or by changing the nominal control voltage ranges.
These values naturally modify the bass tone response as in Figure 2 and Figure 3. With pins 7 loudness and 12 volume directly connected, loudness control starts at typically?
Figure 10 and Figure 11 show the effect of resistively offsetting the voltage applied to pin 7 towards the control reference voltage pin Because the control inputs are high impedance, this is easily done and high value resistors may be used for minimal additional loading. It is possible to reduce the rate of onset of control to extend the active range to? The control on pin 7 may also be divided down towards ground bringing the control action on earlier.
This is illustrated in Figure 12, With a suitable level shifting network between pins 12 and 7, the onset of loudness control and its rate of change may be readily modified. Loudness Compensated Volume Characteristic 7 www. Loudness Compensated Volume Characteristic When adjusted for maximum boost in the usual application circuit, the LM cannot give additional boost from the loudness control with reducing gain. If it is required, some additional boost can be obtained by restricting the tone control range and modifying Ct, Cb, to compensate.
A circuit illustrating this for the case of bass boost is shown in Figure The resulting responses are given in Figure 14 showing the continuing loudness control action possible with bass boost previously applied. Loudness Compensated Volume Characteristic www. Tone Characteristic Gain vs Frequency 9 www. As used herein: Life support devices or systems are devices which a are intended for surgical implant into the body, or b support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user.
A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness. National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation.
All other brand or product names may be trademarks or registered trademarks of their respective holders.
Hex software and proteus isis ares pcb simulation files are cdrom drive, MP4 player or different audio sources Hex software and proteus isis ares pcb simulation files are cdrom drive, MP4 player or different audio sources can use. I recently heard a friend in need is a final project realization had the opportunity to practice and my friend did as a final project application. At half-tone control lm controller ds digital potentiometer for setting the 16F and I use integrated. DS is not commercially available sample of a break I think I had it in my hands so I wanted. As an example, mute button menu — back and forth between menus can be done using the lm integrated control located on the bass, treble, volume and balance to the volt input is provided with adjustable voltage is applied. This regulator pin to output 17 which is received.
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