[Photo] BA1404 Stereo FM Transmitting Circuit

BA1404 is one of the few FM transmitting integrated circuits, which makes up for the shortcomings of designing FM circuits with discrete components in the past, and has the function of stereo modulation. Only a few external components can get a beautiful stereo FM signal. Therefore, it has important application value in FM stereo emission and wireless microwave.

1. Main features of BA1404

The main features of BA1404 are as follows:
● Using low voltage and low power consumption design, the voltage is between 1 and 3V, the typical value is 1.25V, the maximum power consumption is 500mW, and the quiescent current is 3mA;
● Integrated stereo modulation, FM modulation, radio frequency amplifier circuit on one chip;
● Less peripheral components required;
● High separation between two channels, typical value is 45dB;
● The input impedance is 540Ω (fin = 1kHz), the input gain is 37dB (Vin = 0.5mV);
● The typical RF output voltage is 600mV.

2. Pin function and working principle

BA1404 is mainly composed of pre-amplifier (AMP), stereo modulator (MPX), FM modulator and RF amplifier.
The stereo front stage is an audio amplifier with two channels. When the input is 0.5mV, the gain is as high as 37dB, and the bandwidth is 19kHz. If there is a component with a frequency higher than 19kHz in the input signal, a low-pass filter must be added to the input, otherwise the separation of the two channels will decrease.
In the stereo modulation group, the 38kHz signal output by the oscillator is modulated in stereo. Usually an adjustable resistor is connected to pins 16 and 17 to obtain the best channel separation.
The modulated signal synthesized by the stereo mixed signal (MPX output signal) and the pilot output signal (PILOT OUT) enters the RF oscillator through pin 12 and performs FM modulation on the carrier wave. The RF signal is amplified and the RF signal is output. The typical value of the RF signal is at Around 600mV.
BA1404 also provides a reference voltage unit VREF. The designer can use this voltage signal to change the capacitance value of the external varactor diode, and then change the oscillation frequency of the carrier. Therefore, as long as the voltage division value of a resistor is controlled, the purpose of changing the transmission frequency can be achieved, which is a relatively unique design.

3. Typical applications

The picture shows the typical application circuit of BA1404. In the figure, the left and right channels input audio signals into the BA1404 through a pre-emphasis circuit. The internal reference voltage is used to change the capacitance value of the varactor diode, thereby realizing the adjustment of the transmission frequency.
Pay attention to the following points when designing:
(1) In order to make the frequency response of the transmitter and FM receiver match each other, a pre-emphasis network needs to be added at the input end, and its time coefficient is 50 μs.
(2) At the 13th and 14th feet, when the stereo mixed signal and the pilot signal output by the stereo modulator are combined, the separation of the stereo channels may be deteriorated, so you must pay attention to the values ​​of the peripheral components of the 12, 13, and 14th feet.
(3) If the output frequency range of the OSC oscillation network is within 76-108MHz, it can be wound around 2.5 turns with a 0.5mm enameled wire on a 5mm iron core, so that the capacitance value of C11 is 47pF. The same should be true for the RF matching network on pin 7.
(4) In order to simplify the application, the following measures can be taken:
● Leave feet 16 and 17 in the air. Because the channel separation has been ensured within the integrated block, the adjustable resistor is only for optimization.
● No need to fine-tune the transmission frequency of the varactor diode, directly short circuit at the varactor tube, so that R3 and D1 can be omitted.
● You can omit the RF matching network on pin 7 and connect directly to VCC.
The emission range of the BA1404 application circuit shown in the figure can reach hundreds of meters. If you want to increase its emission distance, you can add an RF amplifier to the RF output, you can use discrete components, or you can directly choose RF from MAXIM. Power amplifier circuit MAX2611 or MAX2650, they are suitable for matching with BA1404.

Follow WeChat

Interesting and informative information and technical dry goods

Download Audiophile APP

Create your own personal electronic circle

Follow the audiophile class

Lock the latest course activities and technical live broadcast

related suggestion

Infrared diode emission circuit diagram (acousto-optic alarm / TPS604 ...

This article mainly introduces the infrared diode emission circuit diagram (acoustic and optical alarm / TPS604 / wireless headset infrared emission circuit in detail). Wireless Headphones...

Published on 2018-03-09 11:13 • 866 views

315m wireless transmission and reception circuit diagram (wireless transmission / wireless ...

This article mainly introduces the 315m wireless transmission and reception circuit diagram (wireless transmission / wireless reception circuit diagram in detail). The radio remote control circuit consists of radio ...

Published on 2018-03-09 10:54 • 1095 times read

1000m wireless transmission circuit diagram (single tube oscillation C8050 ...

This article mainly introduces the 1000 meters wireless transmission circuit diagram Daquan (single tube oscillation C8050 / high frequency triode / T630 FM transmission circuit ...

Published on 2018-03-09 09:30 • 921 views

Ultrasonic Ranging Electronic Circuit Design Detailed Explanation-Circuit Diagram Read Every Day (17 ...

The ultrasonic generator consists of two piezoelectric plates and a resonance plate. When a pulse signal is applied to its poles, and its frequency is equal to the natural oscillation of the piezoelectric chip ...

Posted at 2015-06-03 11:54 • 13716 times read

Design of wireless laser communication optical transmitter circuit module

In order to improve the communication and information exchange capabilities of modern weapon systems in harsh electromagnetic environments, make full use of the natural secrecy of the laser and reduce the radio frequency ...

Posted at 2014-11-10 15:27 • 2245 times read

Circuit Design of Sending and Receiving Data for Automobile Intelligent Driving Assistant System

The NPX I chip has 4 KB of user programmable space, 4 KB of custom ROM, and a 2D LF input stage. Various sensors ...

Posted at 2014-11-03 15:32 • 735 views

Circuit diagram read every day (19): Infrared remote control transmission and reception in LAN ...

The system selected is the AT89C51 chip of the 51 series. AT89C51 is a programmable erasable read-only storage with 4k byte flashing ...

Posted at 2014-10-09 09:38 • 1697 views

Automotive electronic circuits: tire module circuit diagram

The tire module circuit uses the intelligent embedded sensor MPXY8300 of FREESCALE. This series of sensors integrates the company's ...

Posted at 2012-06-05 14:14 • 2405 views

Schematic diagram of wireless remote control transmitting and receiving circuit

The following figure is the schematic diagram of the wireless remote control transmitter and receiver circuit. Figure 1 The schematic diagram of the wireless remote control transmitter circuit. Figure 2 The schematic diagram of the wireless remote control receiver circuit.

Posted at 2012-05-29 13:01 • 31521 views

Color vertical fish finder transmitter circuit

The transducer transmits and receives ultrasonic waves directly below the bottom of the ship to detect targets under the bottom of the ship. The difference is that the former uses fish as the main detection ...

Posted at 2012-04-16 15:02 • 1242 times read

Four-way remote control transmitter circuit

The four-way remote control transmitter circuit is mainly composed of a 315MHz wireless data transmission module and a code integrated PT2262.

Posted on 2011-12-24 00:10 • 3757 views

Remote control toy car launch circuit

Electronic enthusiasts provide you with a remote control toy car launch circuit, hoping to inspire your creativity.

Published on 16:56 2011-06-30 • 1790 views

Video transmitting circuit using discrete components

The video signal is firstly amplified by a reverse phase, and then input to the AM modulation stage through the emitter follower; the transmission frequency is generated by the LC high-frequency oscillator and sent to the AM modulation ...

Posted on 2011-01-23 10:44 • 1292 times read

BA1404 stereo FM transmitter circuit (power amplifier, field strength circuit ...

BA1404 Stereo FM transmitter circuit (power amplifier, field strength circuit)

Posted at 2009-12-22 11:13 • 915 views

Transmitting circuit made by LM317

LM317 AFM transmitter Transmitter circuit made by LM317

Posted at 2009-12-22 10:47 • 1091 views

2m FM 144M-148M transmitter circuit

2m FM 144M-148M transmitter circuit Near-Earth Telemetry (Morse Code ...

Posted at 2009-12-22 10:15 • 1133 views

FM transmitter circuit made with discrete (patch) components

This SMD FM transmitter has ...

Posted at 2009-12-22 10:07 • 915 views

4W FM transmitter circuit diagram

4W FM transmission circuit diagramTECHNICAL CHARACTERISTICS: Stabilise ...

Posted at 2009-12-22 10:05 • 1,082 views

Design of Ultrasonic Transmitting Circuit for Low Voltage Power Supply

Ultrasonic transmission circuit design of low-voltage power supply Ultrasonic application fields are very broad, such as military sonar technology, industrial nondestructive testing, testing ...

Published on 2009-10-26 14:02 • 1432 views

Simple FM transmitter circuit

Simple FM transmitter circuit 1.5V-10m3V-30m working current: <= 0.5mA24 # enameled wire at 0.6c ...

Posted at 2009-10-21 17:09 • 822 views

96Mhz FM transmitter circuit diagram

96Mhz FM transmitter circuit diagram

Posted at 2009-04-10 17:30 • 721 views

56M video image transmission circuit diagram

56M video image transmission circuit diagram The radio frequency transmission circuit generates a frequency of 56MHz through a three-point capacitor, and the image signal is collected by the camera ...

Published on 2009-04-10 17:29 • 1681 times read

On-site signal fiber transmission transmitter circuit

On-site signal fiber transmission transmitter circuit

Posted on 2009-02-12 07:52 • 314 views

Voice modulation optical transmission circuit

Voice modulation optical transmission circuit

Posted on 2008-12-21 01:42 • 255 views

50khz frequency light emitting circuit

50khz frequency light emitting circuit

Posted on 2008-12-21 01:40 • 272 views

50M FM wireless headset transmitter part circuit

Figure 3 is a practical 50m FM wireless headset transmitter part of the circuit. The circuit is divided into

Posted on 2008-10-18 08:58 • 482 views

[Photo] Practical home TV station transmission circuit

â—† Overview of circuits Many homes now have televisions

Published on 2006-04-17 19:13 • 385 times read

Simple frequency modulation transmitting circuit with stable frequency

The working voltage is 9V, the working current is 2 ～ 6mA, the component parameters are as shown in the figure, BG1 ...

Published on 2006-04-16 19:25 • 399 times read

Long-distance FM frequency modulation transmitting circuit

The low-power FM transmitting circuit introduced in this article, due to the use of a dedicated transmitting tube, the degree of modulation ...

Published on 2006-04-16 19:25 • 333 times read

800-meter transmitting circuit using acoustic meter resonator

Posted at 2006-04-16 19:22 • 955 views

[Photo] AM audio transmission circuit

Posted at 2006-04-15 20:59 • 1101 views

[Photo] Remote FM transmitter circuit made with LM389

Posted at 2006-04-15 20:53 • 645 views

[Photo] 8050 single tube launch circuit

Published on 2006-04-15 20:52 • 1366 times read

[Photo] 100-108Mhz / 10-15W launch ...

3-Meter Zender (100-108Mhz / 10-15 ...

Published on 2006-04-15 20:50 • 374 times read

[Photo] BA1404 5W circuit

Posted at 2006-04-15 20:50 • 221 times read

[Photo] 1000-meter single-tube oscillation (C8050) FM transmission ...

For an amateur radio enthusiast, getting a good FM transmitting circuit is like picking up ...

Posted at 2006-04-15 20:47 • 630 views

[Photo] BA1404 1907 3953 194 ...

Published on 2006-04-15 20:46 • 202 times read

[Photo] BA1404 modulator circuit

BA1404

Posted at 2006-04-15 20:45 • 561 times read

[Photo] Simple frequency modulation transmitting circuit with stable frequency

The working voltage of this circuit is 9V, working ...

Published on 2006-04-15 20:45 • 760 views

[Picture] Making Frequency Modulation Transmitting Circuit with TA7335

The author refers to the "simple and easy-made integrated FM speech" published in the 21st issue of "Electronic Newspaper" in 1993 ...

Published on 2006-04-15 20:43 • 284 times read

[Photo] BA1404 / 1404F FM stereo transmission ...

Published on 2006-04-15 20:40 • 362 times read

'+ data.username +'

Quit '; * / var login_content =' write an article

'+ data.username +'

Set exit '; $ (' # login_area '). Html (login_content); var win_width = $ (window) .width (); if (win_width> 1000) {$ ("# mine"). MouseDelay (200) .hover (function () {$ ("# mymenu"). show ();}, function () {$ ("# mymenu"). hide ();});}} else {var content = 'Login Registration'; $ ('# login_area'). html (content); $ (". special-login"). click (function (e) {$ .tActivityLogin (); return false;});}});} $ (function () {// comment ------------------------------- var comment = $ ("# comment"); var comment_input = $ ("# comContent"); // Submit comment click event interaction $ ("# comSubmit2"). on ('click', function () {var content = comment_input.text (); // Empty input box comment_input. html (""). focus (); // Submit data to server $ .ajax ({url: '/plus/arcComment.php', data: {aid: $ ("# webID"). val (), dopost : 'apiPubComment', content: content}, type: 'post', dataType: 'json', success: function (data) {// Data format returned: if (data.status == "successed") {// Build temporary comment DOM var dom = ''; dom + = '

'; dom + =' '; dom + ='

'; dom + ='

'+ data.data.username +' '; dom + ='

'; dom + =' '+ content +' '; dom + =' '; dom + =' just now '; dom + =' '; dom + =' '; // insert a temporary comment to the list $ ("# comment ") .append (dom);} if (data.status ==" failed ") {// alert (data.msg); layer.msg (data.msg);}}}); return false;}); (function () {/ * * Insert single sign-on JS * / var setHost = 'https://passport.elecfans.com'; // Set domain name var script = document.createElement ('script'); script.type = 'text / javascript'; script.src = setHost + '/public/pc/js/t.passport.js'; script.setAttribute ("id", "sso_script"); script.setAttribute ("data-ssoSite", setHost); script.setAttribute ("data-ssoReferer", encodeURIComponent (location.href)); script.setAttribute ("data-ssoSiteid", "11"); var body = document.getElementsByTagName ("body"). item ( 0); body.appendChild (script);}) () / * * It is recommended to modify the style of the article without a picture * * / $ (". Article .thumb"). Each (function () {if ($ (this). find ('img'). attr ('src') == "") {$ (this) .find ('img'). remove (); $ (this) .parent (). css ('padding-left ',' 0px ');}}); / * Baidu share * / window._bd_share_config = {common: {bdText: '', // Custom share content bdDesc: '', // Custom share summary bdUrl: window.location.href, // Custom share URL address bdPic: ''} , share: [{"bdSize": 60, "bdCustomStyle": true}]} with (document) 0 [(getElementsByTagName ('head') [0] || body) .appendChild (createElement ('script')). src = 'http://bdimg.share.baidu.com/static/api/js/share.js?cdnversion=' + ~ (-new Date () / 36e5)]; var add_url = '/ d / article / write / '; // var check_allow = "{: U (' Api / iscantalk ')}"; var check_allow = "/ d / api / iscantalk"; var click_items_length = $ ('. art_click_count '). length; if ( click_items_length> 0) {var id_str = ''; $ ('. art_click_count'). each (function () {id_str + = $ (this) .attr ('data-id') + ',';}) // var url = "{: U ('Api / getclickbyids')}"; var url = "/ d / api / getclickbyids"; var id_data = 'id_str =' + id_str; $ .ajax ({url: url, data: id_data, type: 'post', dataType: 'json', success: function (re) {if (re.list.length> = 1) {var list = re.list; for (var i in list) {var t emp_id = list [i] ['id']; var temp_span = $ (". art_click_count [data-id =" + temp_id + "]") temp_span.html (list [i] ['click']);}} }})} $ ("# comContent"). click (function () {if (now_uid == '') {$ .tActivityLogin (); return false;}}) $ (function () {var follow_wrap = $ ( ".author-collect"); var now_uid = "{$ _super ['uid']}"; var face_src = "{$ _super ['uface']}"; var getFollowNum = $ (". followNum strong"). html (); // Follow $ (window) .on ('click', '.author-collect', function () {if (now_uid == '') {$ .tActivityLogin (); return false;} if ( $ (this) .attr ('id') == 'follow') {$ .post ('/ d / user / follow', {tuid: article_user_id}, function (data) {// Data format returned: if (data.status == "successed") {$ (". followNum strong"). html (++ getFollowNum); follow_wrap.html ('followed'). attr ('id', 'cancelFollow'). css ( 'background', '# 999'); var follow_user = ' '; $ (' # follow_list '). append (follow_user);} if (data.status == "failed") {alert (data.msg);}});} else {// Unfollow if ($ ( this) .attr ('id') == 'cancelFollow') {$ .post ('/ d / user / cancelFollow', {tuid: article_user_id}, function (data) {// Data format returned: if (data .status == "successed") {follow_wrap.html ('Follow'). attr ('id', 'follow'). css ('background', '# f90'); $ (". followNum strong"). html (-getFollowNum); $ ('# follow_list .face'). each (function () {var target_uid = $ (this) .attr ('data-uid'); if (target_uid == now_uid) {$ ( this) .remove ();}})} if (data.status == "failed") {alert (data.msg);}}); return false;}}});});}); / * var myface = "{$ _super ['uid'] | avatar}"; var myname = "{$ _super ['username']}"; var article_id = {$ article ['id']}; var article_user_id = {$ article ['mid']}; // Article author ID $ (function () {<notempty name = "clearnum"> // Reduce the number of reminders var count = parseInt ($ ("# noticeCount"). html ()); count = count-{$ clearnum}; $ ("# noticeCount"). html (count); if ( count

Steel Pole 

Pole Height: Hot-Dip Galvanized, Q235 Painting Plastic,4M-15M For Choosing

Pole And Lamp Fixture Color: Grey, White, Black, Blue, Green, Etc

Pole Shape: Tapered, Square, Hexagonal, Octagonal, Etc

Testing Including: 

1.Material testing

2.Shape testing 

3.testing after Galvanizaiton 

4. Tensile testing 

5.Fittings check

Steel Pole

Steel Pole,Galvanized Steel Pole,Street Lamp Steel Pole,Steel Solar Street Light Pole

Yangzhou Bright Solar Solutions Co., Ltd. , https://www.cnbrightsolar.com