The HF7070 HF/LF Communications Receiver …

Colin Horrabin, G3 SBI. 17 Denbury Ave, Warrington, Stockton Heath, WA4 2BL, United Kingdom; The HF7070 HF/LF . Communications Receiver Prototype A detailed look at high performance Receiver design. The HF7070 Receiver is a double con- version superheterodyne with a first IF at 45 MHz and a second IF that is centered at 44 kHz before going to a 25 bit audio ADC. The output from the ADC goes to an advanced 24 bit fixed-point DSP system. The radio covers dc to 30 MHz and has a noise figure of 12 dB without the use of a preamplifier before the first mixer. Out-of- band IP3 at 50 kHz spacing is 45 dBm, giv- ing an SSB IP3 dynamic range of 115 dB. The IP3 within the 15 kHz bandwidth of the roofing filters is 19 dBm at 100 Hz spacing in an SSB bandwidth, which results in an IP3 dynamic range of 97 dB. This in-band linearity sets new standards for an up-con- version radio and gives superb high fidelity reception of FM, AM, SSB and CW signals.

QEX – July/August 2013 39 FST3125. The choice of Mini-Circuits trans - formers used in this mixer gives the radio an out-of-band IP3 of 45 dBm at a 50 kHz test

Tags:

  Communication, Hf lf communications

Information

Related search queries