Fullscreen HTML5Med Res (??MB)HTML4

PRODUCT SHOWCASE Tek's new Wavemeter – a scope & multimeter combination While there are a number of combination multimeter/scopes on the market, this new instrument from Tektronix breaks new ground. The Tek Wavemeter looks very similar to a conventional digital multimeter but incorporates an oscilloscope display with a bandwidth of 5MHz. The Tek Wavemeter is just a little bulkier than conventional upmarket digital multimeters and measures 90mm wide, 208mm long and 45mm deep, at its thickest point. The LCD screen is cranked up to make viewing easier and this factor makes it bulkier than it otherwise would be. Designated the THM420, the instrument is a fully autoranging true-RMS 4000 count multimeter with bargraph display. When you consider that it is priced at around the same level as competing upmarket multimeters, the fact that it has a scope display as well is a major achievement. As such, it will be of great interest to technicians and engineers who need to monitor signal characteristics such as noise, glitches or distortion in conjunction with meter measurements. In meter, mode the 3-3/4 digit (4000 count) instrument is capable of meas- uring full scale DC voltages of 400mV, 4V, 40V, 400V and 850V The true­RMS reading AC ranges are similar except that the top range is 600V AC and DC current ranges are 400mA and 8A. A nice feature is the overrange display. Whereas most meters show a leading "1" in the overrange condi­ tion, the THM420 is clearly unam­biguous – it displays "OV.ER". The six resistance ranges are 400W, 4kW, 40kW, 400kW, 4MW and 40MW, while the frequency meter ranges are 100Hz, 1kHz, 10kHz, 100kHz and 1MHz, with the lowest measurable frequency being 10Hz. The continuity and diode test functions are cunningly combined in one switch position. If the resistance be­tween the probes is 300 or less, the internal beeper sounds and if a diode is connected, the voltage drop across it is measured and displayed. The maximum displayed forward voltage is 2.480V and it can supply enough Fig.1: the multimeter display has large numerals & a bargraph to indicate rapid fluctuations in the measurement. Fig.2: this scope display shows a pulse waveform with a vertical sensitivity of 2V/div and a timebase setting of 100µs/div. Meter mode 88  Silicon Chip current to light LEDs (including blue ones). Scope mode The scope display has a central hori­ zontal axis with eight divisions while the vertical axis has four divisions, each division consisting of 16 dots. The vertical bandwidth is DC to 5MHz from 20mV/div to 1V/div and 3MHz for 2V/div and up. The sample rate is 16Ms/s and the resolution is 6 bits. The horizontal sweep time ranges from 100ns/div to 10s/div. Obviously the only waveforms that can be dis­ played are voltage and current. Controls The controls consist of a rotary se­ lector switch and six rectangular push buttons labelled AUTO, DC/AC, ME­TER/SCOPE, RUN/HOLD, PRINT and LIGHT There is also a cluster of five buttons, the centre square one labelled SELECT, surrounded by four triangu­ lar buttons which point up, down, left and right. The rotary selector switch has an OFF position and six function posi­ tions: Volts, Ohms, Diode, Frequency, mA and Amps. The Volts, mA and Amps legends are highlighted with a blue surround, indicating that when these ranges are selected, the scope mode can be enabled. On the con- Fig.3: this display shows an additional horizontal cursor to indicate the trigger point and a central vertical axis. Styled like a conventional digital multimeter, Tek's Wavemeter doubles as a scope with a bandwidth of 5MHz. This can be brought into play when ever the voltage or current ranges are selected. The scope mode is completely automatic and selects the timebase and vertical sensitivity for optimum waveform display. trol buttons, the words SCOPE and SELECT are screened in blue, tying their functions back to the selector switch. It is difficult to describe but simple to use. One unusual feature is the selec­tion of DC or AC for voltage and cur­rent. This is not selected by the rotary switch as is normal, but is carried out by using the DC/AC button, the last selected function being stored when the power is turned off. This mode also sets the input coupling (ie, DC or AC) in SCOPE mode. The AUTO mode of operation comes into play when the Tek Wavemeter is turned on and this is the setting which would be used most often. Should the need arise, this can be overridden by pressing the up or down arrows to manually select the required range. Unfortunately, in the American manner, the UP and DOWN buttons work in the opposite manner to that ex­pected, the UP button decrementing the Ohms ranges. In SCOPE mode the centre button, SELECT, as the name implies, allows manual selection of trigger, scale and position with successive presses. TRIGGER allows the up and down ar­rows to move a dotted cursor up or down about the reference for positive or negative triggering. With SCALE selected, the up and down arrows change input ranges while the left and right arrows control the timebase speed. POSITION, as its name suggests, al­ lows the up and down arrows to move the trace about the horizontal axis, similar to the Y shift control on a conventional oscilloscope. The left and right arrows move the Y axis from the lefthand side to the centre, and to the righthand side, allowing the pre­and post-trigger waveform to be viewed, just as you can with most digital sampling scopes. We found the THM420 Wavemeter intuitively simple to use. Without using an instruction manual, the ranges are easily selected and a few minutes spent with a function generator and "pressing buttons" will soon give a good working knowledge of the capabilities of the unit. Reading the manual gives an in­sight into functions and capabilities that are not obvious. For example, if the right arrow is held down when the unit is turned on, the auto power off mode is disabled. The auto power off mode is 10 minutes but it is good to be able to turn it off when signals have to be monitored for long periods without touching the control settings. Battery life from the six internal alkaline AA cells is relatively short, at around 10 hours. However, the bat­tery pack clips off the back readily and appears to have provision for re­charging if nicads were employed. A companion printer will be available, which will receive data via an infrared light beam (945nm) from the Wavemeter. It is claimed that the two units will communicate over a distance of one metre The THM420 Wavemeter comes complete with test leads and batteries. A soft carrying case is available as an option. While we did not have the review instrument in our laboratory for long, we feel that its great measurement capabilities combined with ease of use will make it a landmark product that it is sure to be a winner. It is priced at $865 plus tax. For further information, contact Tektronix Australia Pty Ltd, 80 Waterloo Road, North Ryde NSW 2113. Phone (02) 888 7066 or fax (02) 888 0125. Digital video encoder for NTSC & PAL The new Philips SAA7185 digital video encoder is MPEG-compatible and is intended for use in computers, video servers, video CD players and video games. It encodes digital YUV data into an NTSC or PAL CBVS and S-video to be displayed on consumer TV sets or recorded on VCRs. The SAA7185 is an economical solution requiring no licence payments to Macrovision Inc because it does not contain Macrovision's anti-taping cir­cuitry. The SAA7185 is a programmable 5V CMOS device controlled via an July 1995  89 New range of D back shells with multiple cable entry Amtron has released a new series of "D" subminiature back shells for use in the electronics and communications industries. Currently, 9, 15 & 25-way versions are available, while 37 & 50-way versions will be available later this year. All back shells are offered with or without RF shielding. The major feature of this new product is the number of cable entry points available. The 9-way version has two entries, the others have three, which are 60°, straight and 90° The shielded backshell has been tested to MIL STD 285. Each backshell comes with a set of different diameter grommets to suit various cable sizes. For further information, contact Amtron Australia Pty Ltd, 687 Gardeners Rd, Mascot, NSW 2020. Phone (02) 317 5511. KITS-R-US PO Box 314 Blackwood SA 5051 Ph 018 806794 TRANSMITTER KITS $49: a simple to build 2.5 watt free running CD level input, FM band runs from 12-24VDC. •• FMTX1 FMTX2B $49: the best transmitter on the market, FM-Band XTAL locked on 100MHz. CD level input 3 stage design, very stable up to 30mW RF output. $49: a universal digital stereo encoder for use on either of our transmitters. XTAL locked. •• FMTX2A FMTX5 $99: both FMTX2A & FMTX2B on one PCB. FMTX10 $599: a complete FMTX5 built and tested, enclosed in a quality case with plugpack, DIN input •connector for audio and a 1/2mtr internal antenna, also available in 1U rack mount with balanced cannon input sockets, dual VU meter and BNC RF $1299. Ideal for cable FM or broadcast transmission over distances of up to 300 mtrs, i.e. drive-in theatres, sports arenas, football grounds up to 50mW RF out. FMTX10B $2599: same as rack mount version but also includes dual SCA coder with 67 & 92KHz subcarriers. • AUDIO Audio Power Amp: this has been the most popular kit of all time with some 24,000 PCBs being •soldDIGI-125 since 1987. Easy to build, small in size, high power, clever design, uses KISS principle. Manufacturing rights available with full technical support and PCB CAD artwork available to companies for a small royalty. 200 Watt Kit $29, PCB only $4.95. AEM 35 Watt Single Chip Audio Power Amp $19.95: this is an ideal amp for the beginner to construct; uses an LM1875 chip and a few parts on a 1 inch square PCB. Low Distortion Balanced Line Audio Oscillator Kit $69: designed to pump out line up tone around studio complexes at 400Hz or any other audio frequency you wish to us. Maximum output +21dBm. MONO Audio DA Amp Kit, 15 splits: $69. Universal BALUN Balanced Line Converter Kit $69: converts what you have to what you want, unbalanced to balanced or vice versa. Adjustable gain. Stereo. • • •• COMPUTERS I/O Card for PCs Kit $169: originally published in Silicon Chip, this is a real low cost way to interface •to Max the outside world from your PC, 7 relays, 8 TTL inputs, ADC & DAC, stepper motor drive/open collector 1 amp outputs. Sample software in basic supplied on disk. PC 8255 24 Line I/O Card Kit $69, PCB $39: described in ETI, this board is easy to construct with •onlyIBM3 chips and a double sided plated through hole PCB. Any of the 24 lines can be used as an input or output. Good value. 19" Rack Mount PC Case: $999. •• Professional All-In-One 486SLC-33 CPU Board $799: includes dual serial, games, printer floppy & IDE hard disk drive interface, up to 4mb RAM 1/2 size card. PC104 486SLC CPU Board with 2Mb RAM included: 2 serial, printer, floppy & IDE hard disk $999; VGA •PC104 card $399. KIT WARRANTY – CHECK THIS OUT!!! If your kit does not work, provided good workmanship has been applied in assembly and all original parts have been correctly assembled, we will repair your kit FREE if returned within 14 days of purchase. Your only cost is postage both ways. Now, that’s a WARRANTY! KITS-R-US sell the entire range of designs by Graham Dicker. The designer has not extended his agreement with the previous distributor, PC Computers, in Adelaide. All products can be purchased with Visa/Bankcard by phone and shipped overnight via Australia EXPRESS POST for $6.80 per order. You can speak to the designer Mon-Fri direct from 6-7pm or place orders 24 hours a day on: PH 018 80 6794; FAX 08 270 3175. 90  Silicon Chip I2C serial interface or via an 8-bit microprocessor port. It can be syn­chronised as master or slave to external de­ vices. The SAA-7185 also pro­vides an 8-colour on-screen display and "line 21" closed caption encoding. For more information, contact Philips Components, 34 Waterloo Rd, North Ryde, NSW 2113. Phone (02) 805 4479 or fax (02) 805 4466. Video intercom for the home has optional solenoid door release For those who want to see and hear who is ringing their doorbell Dick Smith Electronics now has the answer – the Look-C Door Vision intercom. This unit has a CCD video camera which is mounted outside the front door. When the visitor presses the call button, a chime is triggered while their image is dis­played on a monitor inside the home. The system in­cludes a 2-way intercom so that the householder can talk to, as well as see, the visitor. The CCD camera includes infrared LEDs for illumina­ tion at night, providing an extra degree of security since the caller does not see the light. The camera has auto iris so that it adjusts automatically to a wide range of lighting conditions. An optional solenoid door release is available to com­ plete the package which may be professionally installed or installed by the do-it-yourself owner. The system is available from all Dick Smith Electronics stores at $599. (Cat L-5800). Surplus display module from Oatley Electronics The Hitachi LM215XB, a 480 x 128 dot liquid crystal display (LCD) module, is now available from Oatley Elec­ tronics. This brand new unit, which costs $25, comes complete with an attractive housing, a mating connector and data sheet. The module is 270 x 110 x 11.5mm and needs a 5V positive supply and a negative supply of around lOV to operate. For further details on this LCD module contact Oatley Electronics, PO Box 89, Oatley, NSW 2223. Phone (02) 579 4985 or fax (02) 570 7910. AUDIO TRANSFORMERS SILICON CHIP SOFTWARE Stereo TV sets with multi-system compatability ORDER FORM Akai has announced three multi-system stereo colour TVs which comprise the 68cm CTK-2976 and CTK-2877A models, and the 59cm CTK-2577A set. All models offer audio outputs for connection to home stereo systems and all are compatible with up to 23 TV and VCR playback systems, including NTSC, SECAM and several PAL formats. All three models feature program memory, auto search tuning, infrared remote control, dark tint tube, on-screen menu display and a sleep function, which turns the power off after a preset time. The CTK-2976 (RRP $1399), CTK2877A ($1499) and the CTK-2577A ($1299) are covered by a 12-month warranty and are available at selected Akai dealers and department stores. For further information on these colour TV sets, contact Akai on (02) SC 763 6300. PRICE ❏ Floppy Index (incl. file viewer): $A7 ❏ Notes & Errata (incl. file viewer): $A7 ❏ Alphanumeric LCD Demo Board Software (May 1993): $A7 ❏ Stepper Motor Controller Software (January 1994): $A7 ❏ Gamesbvm.bas /obj /exe (Nicad Battery Monitor, June 1994): $A7 ❏ Diskinfo.exe (Identifies IDE Hard Disc Parameters, August 1995): $A7 ❏ Computer Controlled Power Supply Software (Jan/Feb. 1997): $A7 ❏ Spacewri.exe & Spacewri.bas (for Spacewriter, May 1997): $A7 ❏ I/O Card (July 1997) + Stepper Motor Software (1997 series): $A7 POSTAGE & PACKING: Aust. & NZ add $A3 per order; elsewhere $A5 Disc size required:    ❏ 3.5-inch disc   ❏ 5.25-inch disc TOTAL $A Enclosed is my cheque/money order for $­A__________ or please debit my Bankcard   ❏ Visa Card   ❏ MasterCard ❏ Card No. Signature­­­­­­­­­­­­_______________________________ Card expiry date______/______ Name ___________________________________________________________ PLEASE PRINT Street ___________________________________________________________ Suburb/town ________________________________ Postcode______________ Send your order to: SILICON CHIP, PO Box 139, Collaroy, NSW 2097; or fax your order to (02) 9979 6503; or ring (02) 9979 5644 and quote your credit card number (Bankcard, Visa Card or MasterCard). ✂ Manufactured in Australia Comprehensive data available Harbuch Electronics Pty Ltd 9/40 Leighton Pl. HORNSBY 2077 Ph (02) 476-5854 Fx (02) 476-3231 Now available: the complete index to all SILICON CHIP articles since the first issue in November 1987. The Floppy Index comes with a handy file viewer that lets you look at the index line by line or page by page for quick browsing, or you can use the search function. All commands are listed on the screen, so you’ll always know what to do next. Notes & Errata also now available: this file lets you quickly check out the Notes & Errata (if any) for all articles published in SILICON CHIP. Not an index but a complete copy of all Notes & Errata text (diagrams not included). The file viewer is included in the price, so that you can quickly locate the item of interest. The Floppy Index and Notes & Errata files are supplied in ASCII format on a 3.5-inch or 5.25-inch floppy disc to suit PC-compatible computers. Note: the File Viewer requires MSDOS 3.3 or above. July 1995  91