The TNR-HFR receiver is a wide dynamic range high-resolution spectrometer integrating two channels in interface with the three monopoles for the electric field and the high frequency magnetic search-coil. TNR produces quasi-instantaneous spectra for the electrostatic thermal noise and/or the magnetic field in the range 4 kHz - 1MHz. HFR is a sweeping receiver, operating in the range 500 kHz over-16MHz, for the survey of high frequency radio emissions. Since a high amplitude resolution is required on the whole dynamic, the receiver adjust the gain according to the input level. The AGC loop (Automatic Gain Control) defines the receiver gain by normalizing the amplitude at the input of A/D converters thus providing a wide dynamic range. By using low noise linear preamplifiers, the dynamic range reaches 120dB for the TNR range and 80dB for the HFR one.

TNR

By making use of sharp analog filters the TNR frequency range is divided into four sub-bands of 2-octaves. By using a wavelets-like transform, the digitized waveform of each sub-band is processed and auto- correlations and cross-correlations are calculated for 32 log-spaced frequencies (Delta f/f 4.5%), resulting is a total of 128 log-spaced frequencies.

• Band A: 4 kHz-16 kHz. 32 log-spaced frequencies.
• Band B: 16 kHz-64 kHz. 32 log-spaced frequencies.
• Band C: 64kHz-256kHz. 32 log-spaced frequencies.
• Band D: 256 kHz- 1024 kHz. 32 log-spaced frequencies.

HFR

It down-converts the input signals using a super-heterodyne technique. The TNR channels offer complementary signal conditioning to enhance the dynamic range. Spectra are measured simultaneously on both channels with a linear resolution. The HFR is highly programmable. Up to 324 frequencies can be selected between 0.4 and 16.4 MHz. In normal mode, the duty cycle for one frequency channel is 27 ms and the number of analyzed frequencies is 192. This yields a full HFR spectrum scan in 5.2 s.