Nma0515 pdf

A heat -sink is not is not a mistake! While the IC is in The programming cycle is started as needed on the The min- stored in the RAM. The information imum value is required to ensure the conveyed over the bus may also be proper programming voltage, while the copied into the register by controlling maximum value must be observed to the C input pin This happens with prevent the from being destroyed one byte only: the configuration word.

The parts As long as U8 is in high -Z mode, the list mentions a V mains adaptor. The PIC17C42 to be pro- siderably higher output voltage than grammed reads the configuration the nominal value when the load cur- stored in this register with the aid of a rent is relatively low. Just to make sure pulse on port PC3. Only during this it is suitable for the job, the adaptor's pulse is the register released from its output voltage should be checked with high -Z state.

Since the outputs of U5 the programmer connected. If you use and U3 are then at high impedance, the processor to be programmed. In other words, U8 The programming algorithm used The desired programming voltage, acts as a one -byte wide memory with a enables selected bytes to be pro- Vprog, and the supply voltage, VDD, depth of one location, and is used for grammed individually, and to be read are regulated by the PWM1 and PWM2 intermediate storage of the processor back for verification.

This allows the outputs of the P1C17C42, U5. These configuration word. MSDOS PC, and serves to define pro- ming and verification in a simple man- The roll -off frequency of the filters built gramming parameters including the ner.

For these controllers, the signal tween 0 and 5 V depending on the duty The programming status informa- arrangement on the ZIF socket is mod- factor of the PWM signal. Despite the tion may be found on pins PCO and ified.

Switch UIOA is opened because simplicity of the filter sections, the di- PC1 of the PIC17C42 to be pro- pin 9 is to be used for the programming rect output voltages are sufficiently grammed.

These outputs are low dur- voltage. If the supply voltage is applied to the socket ripple. The filter is followed by a d. In completed, PCO goes high. If not, PC I gramming voltage. The programming this way, a variable output voltage of goes high. The output imped- while the test input is made high. This These processors are programmed ance of the opamps is low enough to.

Event driven Digital Simulation with modelling language. Graphs displayed directly on the schematic. Loam toismonamaziamaaammutarans. Electron i C S Tel: Fax: All manufacturers' trademarks acknowledged. PC As with the 16C5x, two as for other, comparable, 8 -bit tor. The fourth oscillator option cycles are needed for a jump PIC17C42 processors.

Furthermore, PIC is the use of an already avail- instruction, The processor rec- The 17C42 is largely similar to processors contain circuitry to able clock signal, which may ognizes four interrupt sources, the other processors in the reduce power drain and exter- be used on all processors.

However, it has no nal component count of a com- The on -chip A -D converter has fewer than 55 instructions, plete system. General specifications four channels, a sample -and - each of which is executed in The internal power -on reset Clock frequency: d.

At a clock circuit and start-up timer en- Instruction time: infinite to of 8 bits. All op - erly initialized after the power Instruction width: 12 bit conversion time is 30 codes are 16 -bit wide, so that supply is switched on.

L 7 U11 X2 U2. C16 c2, I. C17 O. Track layouts direct reading and component mounting plan of the printed circuit board designed for the PIC programmer PCB avail able ready-made. Fully loaded printed circuit board before mounting in DB3 case. The idea is to make them After starting the program PIC.

This is easily achieved by enter the PIC type to be programmed. Alternatively, use programmer can be selected. The advantage of the file to be burned into the device. Printed circuit board and software this enclosure is that the PCB can be Also shown are the options contained package, order code see page secured with the aid of two strips, in the configuration word.

These op- The file format be programmed. The variable supply you want to reduce fault-finding time. Note may be connected to the PC's serial of this magazine. First, read the file that the LM is supplied direct by port. To keep this link as simple as using the 'File' menu option, and then the adaptor's output voltage.

The 'Prog'. The configuration is burned into Construction link is established by a 9 -to -9 pin ex- the processor by selecting the menu tension cable without crossed wires. If option 'Fuse'. Mind you, the oscillator The PIC programmer is simple to build your PC has a 25 -way serial port con- type selection is fixed by the manufac- on the double -sided, through -plated, nector, use a 25 -to -9 pin adaptor as turer, since it is hardware dependent.

The 'Blank' option allows you to check work is shown in Fig. This board is whether the PIC to be programmed is best ordered ready-made through our Control software empty. The function of 'Quit' is obvi- Readers Services, and comes together ous.

An overview of available com- with the PIC programmer's software The control software for the PIC pro- mands may be called up by typing '? This prevents gram to be run on a PC and 2 a ready -.

The affordable and complete solution for microprocessor development work. We do. So if you question an advertiser. To find out. Use your electronics know-how to create great sound! Within its pages, learn ' I SPeake' lidel about Thiele -Small design software, build an in- expensive measurement mike good enough for the professionals, or simply indulge in reading about the experiences of others using their technical skills to improve the sound around them.

From pipes to corrugated boxes to transmission lines and electrostatics, every conceivable medium is discussed. An international forum for speaker enthusiasts the world over, sharing ideas and designs, Speaker Builder has made it possible for thousands to enjoy the highest quality sound without straining their budgets. Iwith choice of very wide ranges of famous -name The publishers of Speaker Builder invite you to use your electronics know-how to quality electronic components and associated gear discover the world of better sound.

To subscribe, simply return the form below with sent promptly on receipt of your order. Send for your copy NOW! Remittances in US funds drawn on a US bank only. Tel: Call us now! We hay the widest range of comp nents available At competitive prices! I P, Tr' I. This series is intended to help you with the quantitative aspects of electronic design: predicting currents, voltage, waveforms, and other aspects of the behaviour of circuits.

Our aim is to provide more than just a collection of rule -of -thumb formulas. We will explain the underlying electronic theory and, whenever appropriate, render some insights into the mathematics involved. We continue the exploration of equation for a parallel LCR cir- zero: equal: circuit modelling by extending cuit is similar see Eq.

In Part 13 we these cimple circuits by using the left. The result ditions. At we assume that the right-hand [Eq.

If fact that the voltage is ramp- dt L dt LC side of the equation, so that the this is so, then: ing. This was based on the fact that age is constant. If t made. More often, the voltage, u, An example shows how to find Eq. For the particular integral. Suppose example, it may ramp up or down that in Fig. We a rate of 20t2. The highest power of t 2 k cos t dt2 L dt LC L dt d is tl. For Eq. Part 13 shows how this equa- To find the CF, put the right- be satisfied by all possible values Box 1.

Functions for particular tion is obtained. The form of the hand side of Eq. Box 1 lists 2 1 forms suitable for other cases. This is the solu- about D. Although we have said tion obtained when two border it is not a variable, it can be conditions are satisfied. Ae-- 10 02 t Aet Operator D really comes into its Fig. We ciable initial 'kick' of Fig. D is not a L produces sin 3t. In words, the cur- erator, which means 'differen- tiate'.

Using this tion in the usual way. The rules of iliary equation is: [Eq. Inserting the second border con- The idea of D is extended to It shows the rapid increase of cur- dition: differentiating a differential.

These must so small, the final expression Note that we do not introduce the have been present as the result dominates the equation. Current constant of integration when we We make use of operator D for of a voltage applied to the cir- increases at the rate of 7. This is why the per second without the appre- Representing Eq. After about 10 ms, the 2. The theorems are fects of the new voltage ramp- stated in Box 2. The ef- 3b. Operator D theorems. First, rewrite Eq. This makes whence the calculation easier than the 1 - 0.

Now look This is the PI. Adding this to at Theorem 3a in Box 2. This tells the CF, we obtain the complete - In this example, we have t as the variable instead of Given two border conditions, we x.

The constant a is equal to 3, can find A and B in the usual way so we replace D2 by , which and so obtain the particular so- is lution. Test yourself We juggle with the fraction on 1. Given the complete solution the right, multiplying top and C1 L1 of Eq. Given the complete solution 9D-, of Eq. Given a circuit as in Fig.

The Answers to PI becomes: nentially. Ae-4t Be t. Thus, the general solution CF set to discharge C1. It can be PI. Writing Eq. It falls to 0. PC Software. All offers subject to availability. Send SAE for complete list of satellite books, videos and software POWERware sou-. All prices inclusive. Increase your 2 '3. Elektor Electronics, which is distributed all over the world, can help you achieve these goals. The value of an annual subscription If you wish to increase your electronics know-how and skills, take out an annual subscription to Elektor Electronics by filling in the order form on page 71 or writing or telephoning to the address below.

You will then not only have the convenience of having the magazine delivered to your home and the peace of mind that you will not miss any issue, but you will also save money compared with buying the magazine from a bookstall: the price of a subscription g'rger N d Spy.

Rates are shown on page Look out for the January and Febru issues of Electronics The Maplin agazine for detailed instructions of ho uild this - superb amplifi r yourself! For details phone, fax or write to: Subscriptions Dept.

Overseas Readers: Electronics - The Maplin Magazine listed in the International Press Directory can be obtained from your local news stockist and by subscription. For details phone, fax or write to: Overseas Subscriptions Dept. Box , Somerset West , South Africa. Tel: 51 Fax: 51 Four models are available to suit the needs of the professional and hobby market i.

Industry, Leisure, Instrumental and Hi-Fi etc. When comparing prices, NOTE that all models include toroidal power supply, integral heat sink, glass fibre P. All models are open and short circuit proof.

Size x x 60mm. Size x x mm. ME GEN. Join the Piezo revolution! The low dynamic mass no voice coil of a Piezo tweeter produces an improved RES. Ideal for RES. Suitable for high RES. PRICE Operates at 11Mhz 28k bytes of program memory, includes many features to aid program development but uses some resources of the target Operation selectable up to 16MHz, 64k bytes of program memory, uses none of the target resources.

Easily customised for any MCS51 family variant. High level language debugger available L HE's worth of discount vouchers H. Aid L L I. I ,I,, I:. AA ,, 11,. L25 Function Generator 0. W1, I. HOT Used Equipment Guaranteed- Manuals supplied if possible Tor, 1s. Although most designs are intended for novices, and lack certain features of high-grade superheterodyne receivers, the modern direct conversion receiver DCR is capable of exciting performance.

Most of the gain which helps grade communications receivers. In older receivers it was al- search and experience building several most universally true that the difference different models bears it out. While no IF frequency was selected KHz and one, least of all this author, would repre- KHz being very common , but in sent the DCR as capable of the best pos- modern communications receivers either sible performance, modern designs are or both might be selected.

For example, it no longer in the hobbiest curiosity cate- is common to use a 9 -MHz IF amplifier gory. In this two-part article you will find on high frequency HF band shortwave the basic theory of operation, some of the receivers. On bands below 9 MHz, the Fig. Block diagram of the heterodyne sum IF is selected while on bands above appropriate circuits, and some of the ac- frequency conversion circuit that forms the tual designs tried on the workbench.

A basis of both the superheterodyne and direct popular combination on amateur radio conversion receivers DCR. The latter cies will also receive the 20 -meter Figure 1 shows the basic block dia- termediate frequencies IF. Other i. The mixer is a nonlinear ele- purposes of this discussion are regarded difference IF frequency is used see ment that combines the two signals, FRF as negligible.

In general, we are only interested in the cases where - I - 12 m and n are either 0 or 1, so the output frequency spectrum of interest is limited Fig.

Block diagram of a generic direct conversion receiver. Ground 2,5,6,7 2,5,6,7 2,5,6,7 telegraphy , and single sideband signals, it is necessary to offset the LO frequency LO In 8 8 8. In my own case, I am most comfortable LO:. Inset shows tuned to either In either case, the beat note heard in the output is Hz. Single sideband SSB reception requires an off- frequency selection at the front end, the mixer that recovers the audio modula- set of the order of 1.

Some designs will in- cuits used in radio receivers, and most of after the first mixer. While the super- clude more than one style of filter. For them are candidates for use in direct con- heterodyne uses the IF amplifier chain example, a popular combination uses a version receivers.

As you will see, how- for this purpose, followed by second de- single staged tuned resonant circuit at ever, not all mixers are created equal, so tection and audio amplification, the DCR the input of the mixer to select the RF some are better suited to DCR applica- must use only the audio amplifier chain.

In nearly all cases, the Thus, it becomes necessary to provide ter - with a cut-off frequency, Fe, of output circuit of the mixer will be a low- some very high gain audio amplifiers and 2, KHz - which is designed to ex- pass filter that passes audio frequencies, audio bandpass filtering in the DCR de- clude AM broadcast band signals.

The but not RF frequencies. Both being of local origin, and is therefore ca- namic range. While this feature can be a prob- The RF amplifier used in the front- the minimum detectable signal and the lem, it has at least one charming end is also optional, and is used to pro- maximum detectable signal. There are attribute on SSB reception: the DCR will vide extra gain, and possibly some some passive mixers that produce so receive LSB signals on one side of zero - selectivity.

The gain is needed to over- much loss, so much noise and require so beat and USB signals on the other side of come losses or inherent insensitivity in much signal strength to operate in the zero -beat. There have been attempts to the mixer design. Not all mixers require first place that they are simply not suited provide single -signal reception of SSB the RF amplifier, so it is frequently to DCR design unless adequate pream- signals on DCRs' by using audio and deleted in published designs.

In general, plification is provided. Below 14 MHz, perheterodyne receivers because they are That approach greatly increases the com- signals tend to be relatively strong and preceded by the gain of the front-end and plexity of the receiver, which may make man-made noise tends to be much the IF amplfier chains, which can be con- other design approaches more reasonable stronger than inherent mixer noise.

First, stage, a local oscillator and an audio am- The principal element in any direct con- there is always the possibility of radia- plifier. In fact, if the mixer has a high version receiver DCR is the mixer. The tion of the local oscillator LO signal enough output signal level, and high im- mixer is a nonlinear circuit that exhibits through the antenna.

In order to prevent pedance earphones are used to detect the changes of impedance over cyclical excur- this problem, it is necessary to keep the audio, some designs can make do without sions of the input signals.

When mixing mixer unilateral, i. These are, however, linear, one signal will ride on the other in one direction. Some mixers are inher- a rarity and the one version that I tried as an algebraic sum, but the product fre- ently good in this respect, while others did not work very well.

A mixer that are a bit problematical. In cases where In some DCR designs, there will be op- produces product frequencies can be used LO radiation might occur it is recom- tional RF input signal conditioning con- either in DCRs or superheterodyne re- mended that an RF amplifier be used sisting of either a low-pass filter, ceivers. In superheterodyne receiver ter- ahead of the mixer, regardless of high-pass filter, or bandpass filter as ap- minology it is common to call the whether or not it is needed for purposes propriate to select the desired signal or frequency translation mixer that pro- of improving sensitivity.

Without some duces the IF a first detector, and the The second problem that must be rec-. Although not an opti- ing action to select input signals. The mal match, the resistance matching output network consists of an audio scheme results in superior performance transformer with a k4 primary and a over randomly selecting the diodes.

SBL-series devices. The pin pattern for the shielded case of these mixers is Considerations for good shown as an inset to Fig. Note that pin 1 is indicated by a It probably does not surprise many read- blue bead insulator around the pin, while ers that there are some principles of good the other pins will have a different color. These mixers are cluding those based on the Signetics used in many published DCR designs, NE integrated circuit double bal- where they have proved an excellent anced modulator' and the popular Fig.

Balanced mixer based on the CA choice. The RF signal must be kept at tion is not without critics. Theoretically any mixer can 1. DCR designs. The SBL- Perhaps the best passive form of other uses simple differential amplifier 1 is designed for 50 Q input and output mixer is the double balanced mixer circuits.

The mixer of Fig. The differential input impedance quencies by the Q resistor R1. This type the differential output impedance pins 6 produces a high reactance at audio fre- of mixer uses the same sort of diode ring to 8 is 8 kQ.

For an input circuit, there- quencies AF , and a low reactance at RF, circuit as the single balanced mixer dis- fore, a transformer is needed that con- the mixer is terminated for any residual cussed above, but adds a second trans- verts the antenna impedance typically LO and RF signal which are absorbed by former to the circuit for the RF signal. In 50 Q to Q. This transformer can R1 , but AF is transmitted to the low- this circuit, the LO signal is driven in have a tapped primary that matches pass filter.

All of these diode mixers can be made with either hot carrier diodes preferred or ordinary silicon small -signal or switching diodes those in the 1N and 1N class are suitable. In either case, performance is improved if the diodes are matched. Block diagram of mixer output circuit used in direct conversion receivers. Direct conversion H.

I -C ; I 4 4'14 '. J tic' Fax 6 Tuning b Voltage. C Some practical design circuit uses the same balanced front-end approaches as other designs and, like the typical NE design, uses the internal oscilla- AF. The circuit following this front- mance for little effort. The NE chip is end should be of the sort typically found relatively easy to obtain, and for the in the NE designs. This particular most part is well behaved in circuits i. It consists of several I ISc.

The NE can provide very good that form both low-pass and high-pass Fig. The values of the induc- the mixer and filter the audio; b audio tively easy to obtain, but lacks something tors L1, L2 and L3 are selected with preamplifier for direct conversion receiver; in dynamic range.

Although the specifi- their d. Campbell used level of dBm7. The matched audio preamplifier sentially flat passband " Campbell implied the use of switch- greatly improved device compared to the According to Campbell, this circuit pro- ing, as shown in Fig. As shown here, The Dillon design shown in Fig. The range of the switching involves use of a pair of uses the push-pull outputs of the NE input signals that it will accommodate ganged SP3P rotary switches. In a short i. According to out undue distortion.

These specifica- PIN diode switched variant for a differ- Dillon, the balanced output approach im- tions make the amplifier a good match to ent purpose, and see no immediate rea- proves the performance, especially in re- the DBM. Like the Lewallen circuit, the son why it shouldn't work.

Also Campbell circuit uses a grounded base A complex DCR was designed by helping the breakthrough problem is the input amplifier T, , and an active decou- Breed, and reported in the amateur radio use of a nF capacitor across the out- pler T2.

But Campbell also adds an literature as a direct conversion single put terminals of the NE These filters tude modulation, for it is a variant of While functionally similar to the NE, are designed for termination in an im- AM that reduces the RF carrier and one the TDA is more complex and is said pedance of Three different band -of the two AM sidebands to negligible to deliver superior performance with re- passes are offered: 1 KHz, 3 KHz and levels.

This mode is used in HF transmis- spect to dynamic range and signal over- 4 KHz. The 4-KHz filter is a fifth order sions because it reduces the bandwidth load characteristics. Figure 7 shows a Butterworth design, while the 3-KHz fil- required by half, and removes the carrier DCR front-end circuit based on the ter is a seventh order elliptical design that produces heterodyne squeels on the TDA after Daulton's design.

This after Niewiadomskim. The Hz de - shortwave bands. The first three of these circuits are recognized according to the nature of their respective feedback networks, while the other is recognized by the special connection of a trans- former.

Note that the Colpitts and Clapp are basically the same circuit, except that the Colpitts uses a parallel tuned LC frequency setting network and a Clapp oscillator uses a series tuned LC network. VFO circuits consist of an active ele- ment transistor, IC, etc. Phasing -style direct conversion receiver for improved single sideband reception. The most common today uses a dou- listening level, while also tailoring the must be in -phase with the amplifier ble balanced modulator to combine a bandpass characteristics of the overall input signal.

In most circuits, there is fixed carrier and the audio signal to pro- receiver to limit noise and other arti- degrees of phase inversion between duce a double sideband suppressed car- facts. Although any number of discrete input and output, so the feedback net- rier output signal; the unneeded and integrated circuit IC circuits are work must provide an additional de- sideband is then removed by filtering.

Figure 10 shows a oscillation. This circuit The LM design of Fig. The splits the incoming RF signal into two single -ended configuration for the high F, prevents unplanned phase components and then feeds them both to LM low -power audio stage.

This IC changes at higher frequencies within the separate mixers. These mixers are dri- device contains both preamplifiers and VFO range. The LM series of more is usually required. The output of the phase grounding is not proper. There are two shift network is filtered in a low-pass fil- basic circuit configurations for the ter and bandpass filter, to provide the re- LM The differential version was covered modulation.

The gain of the circuit can be either 46 dB x when capacitor C2 The audio chain in the direct conversion is used, or 26 dB x20 when C2 is deleted receiver tends to be very high gain in leave pins 1 and 8 open -circuited.

The principal job of the audio am- plifier is to increase the signal level by The local oscillator LO for a continu- ously tunable receiver of any description Fig. Hartley VFO circuit. Although higher grade re- ceivers today typically use frequency synthesis techniques for generating the LO signal, the standard inductor -capaci- tor LC controlled VFO still has appeal for less complex receivers.

There are some cases, however, where a receiver LO has at least one specification that is more rigid than the transmitter equivalent: many receivers have a re- quirement for low FM phase noise. In the main, however, amateur radio applica- Fig. Audio stage based on the LM tions of direct conversion receivers typi- audio integrated circuit.

Colpitts VFO circuit. The oscillating frequency is In the second and final part of this article set by L1 -C1, although the effects of C2, we will look at some practical designs of C3 -C4 and the gate capacitance of the direct conversion receivers. JFET must also be considered. Figure 13 shows a VFO circuit that Notes and references: uses the transformer core to provide out- 1.

Gary A. The main USA, A feedback coil consists of 2 turns QST August , pp. Roy W. Micheal A. Covington, 'Single -chip oscillator more often than not. In addition, because the January , pp. Also avoid wide variation in 7. Niewiadomski, 'Passive Audio Figure 11 shows a Hartley oscillator tor.

Filter Design' Ham Radio September circuit. This type of oscillator is identi- Use an output buffer amplifier to iso- , pp. April , pp. JFET is connected to ground through the serves only the oscillator device but See also the National Semiconductor tap, so its current becomes the feedback not the buffer amplifier.

Linear Data Books, or the data books of signal. The top end of the coil is con- Rigidly mount the frequency determin- other major IC manufacturers for appli- nected to the resonating capacitor and ing capacitors and inductors.

Prefer air core inductors over ferrite or From an article by L. Gunn, K7HFD, be taken from the drain, gate, or source powdered iron core inductors; prefer discussed and cited in W. Hayward and terminals of the JFET, as well as from ei- slug -tuned coils over toroids.

These criteria were developed from the source terminal for output so as to Small capacitors in the frequency de- W. Hayward and D. DeMaw, Solid -State lightly load the oscillator. The normal termining network, or used as coupling Design for the Radio Amateur op-cit. Lightly load the frequency determin- The tuned circuit that sets operating ing LC network by using a small capac- frequency consists of L1 and C1, with L1 itance pF between the tank being tapped for feedback purposes.

In circuit and the gate or base of the oscil- most cases, the tap is between 20 and 40 lator transistor. The cou- If an air variable capacitor is used for pling capacitor between the LC network the main tuning control, then it should and the JFET is a very small value so as be a double bearing model.

The diode in Fig. This diode is a small sig- tuning voltage supply that is regulated nal silicon diode of the 1N or 1N by a varactor controller device such as class.

Figure 12 shows the Colpitts VFO circuit. This circuit can be configured These guidelines are neither exhaustive with a series resonant circuit, in which nor absolute, but following them as case it is called a Clapp oscillator. Both closely as possible will result in a supe- types of oscillator are identified by the rior VFO stability.

Installed in seconds they simply plug directly into either the serial or parallel port. They are completely self contained, require no external power supply and take up no expansion slots. Commitment to Quality: Our stated company goals are to continually improve service , meet ISO Quality Certification , and implement innovative tools like Brokerlynx to protect you from substandard product quality and counterfeit parts while ensuring full traceability on all transactions!

Advocacy against Counterfeiting: Oxygen Electronics is committed to fighting counterfeiting. You can download our educational brochure on how to spot counterfeiting and the very latest list of counterfeited parts from Brokerlynx.

Superior Process: Our proprietary U-Shaped Process integrates every aspect of a transaction, including outside partners , to ensure that the job is done right, while minimizing your vendor database.

And if you are just curious, use our Part Search features! Texas Inst. Purpose 30V 1. Purpose 30V. Purpose 60V 0. Generators Signal 1. Open navigation menu.

Close suggestions Search Search. User Settings. Skip carousel. Carousel Previous. Carousel Next. What is Scribd? Explore Ebooks. Bestsellers Editors' Picks All Ebooks. Explore Audiobooks. Bestsellers Editors' Picks All audiobooks. Explore Magazines. Editors' Picks All magazines. Explore Podcasts All podcasts. Difficulty Beginner Intermediate Advanced. Explore Documents. Libreria Total2. Uploaded by Gabotte Getto. Document Information click to expand document information Original Title Libreria-total2.

Did you find this document useful? Is this content inappropriate? Report this Document. Flag for inappropriate content. Download now. Save Save Libreria-total2 For Later. Original Title: Libreria-total2. Related titles. Carousel Previous Carousel Next.