- on RF (radio)
- Published in issue 2/2005 on page 0
Audio in the ISM band
When the ISM frequency band was made available in Europe for audio applications, Circuit Design, a manufacturer of professional RF modules, decided to develop suitable high-qualitytransmitters and receivers with a wide dynamic range: these are ideal for use in wireless microphones.
The WA-TX-01 (transmitter) and WARX- 01 (receiver) modules represent a novel concept in the wireless transmission of audio signals. Thanks to low power consumption, the technology lends itself to a wide range of audio applications. The transmitter and the receiver include components such as SAW filters, SAW resonators and noise reduction ICs.
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CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor Members can exclusively download these files for free as part of their Membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service. Elektor recommends its business partner Eurocircuits as the company of choice for its own prototypes and volume production in selected cases.
R1 = 2kOhm2
R2,R8 = 560Ohm*
R3,R4 = 220kOhm
R5 = 4kOhm7
R6 = 47Ohm
R7 = 100kOhm
P1,P2 = 10 kOhmpreset
C1,C6 = 4µF7 63V radial
C2,C7 = 100nF
C3,C5,C8 = 10µF 63V radial
C4 = 470nF
D1 = LED, 3mm, green, low current
D2 = LED, 3mm, red, low current
IC1 = WA-TX-01 (Circuit Design)
IC2 = WA-RX-01A (Circuit Design)
IC3 = TS921IN (or equivalent rail-to-rail-opamp)
JP1 = 2-way pinheader with jumper (angled if necessary)
K1 = 3.5-mm jack socket, PCB mount (e.g. Conrad Electronics # 732893)
BT1 = battery holder for two 1.5V batteries
MIC1 = electret microphone
PCB, no. 040402-1