Analyzer Rather Than a Planet, Pluto Serves as a Spectrum Analyzer
Revamped Write-up:
Sick of those RTL-SDR dongles stealing the spotlight? Fear not, my buddy, for the Pluto SDR is a hidden gem in the software-defined radio (SDR) world! [FromConceptToCircuit] offers up some code to transform this bad boy into a top-notch spectrum analyzer that whips through 6 GHz and dives as low as 100 MHz. Check out the video below to witness this marvel in action!
At first glance, a 100 MHz ceiling may seem limiting, but believe it or not, there's plenty of action in that range, from WiFi and Bluetooth to radio systems (both commercial and amateur) and even cell phones.
The system operates at its finest using the lock-in amplifier technique. The Python code is straightforward, allowing you to scan every frequency and determine signal strength at each point. Remember, the real challenge lies in the fine print.
We've tackled harnessing the power of the Pluto SDR with GNU Radio in the past. We dig its network adapter-like connectivity and especially its applications for spectrum analysis, which is a darn common project for these SDRs.
Enrichment Add-On:
Transforming the Pluto SDR into a swanky spectrum analyzer calls for several moving parts, including the hardware setup, software implementation, and calibration. The ADALM Pluto SDR offers a versatile platform for signal processing, but going from a 100 MHz to 6 GHz frequency range is a stretch, given its native capability typically spans from 70 MHz to 6 GHz. However, with some clever software tweaks, you can make it perform magic within its limits!
Hardware Gathering
- Gather your basic machinery: an ADALM Pluto SDR, a USB connection for your computer, an RF bridge or coupler (for a lock-in amplifier setup), and a suitable antenna.
Programming for Profit
Python Programming
Kick things off with Python by employing libraries such as , , and to interact with the ADALM Pluto SDR. Here's a sketch of how you might design a simple spectrum analysis script in Python:
```pythonimport numpy as npfrom scipy.fft import fft, fftshiftimport matplotlib.pyplot as plt
frequen_t_sweep= 1e9 # Hzsample_r_t= 1e6 # Hznum_samples= 1024
time = np.arange(num_samples) / sample_r_tsignal = np.sin(2 * np.pi * frequen_t_sweep * time) # Example signal
fft_signal = fft(signal)
fft_shifted = fftshift(fft_signal)
freqs = np.fftshift(np.fft.fftfreq(num_samples, d=1/sample_r_t))plt.figure()plt.plot(freqs, np.abs(fft_shifted))plt.xlabel('Frequency (Hz)')plt.ylabel('Amplitude')plt.title('Spectrum')plt.show()```
GNU Radio Action
GNU Radio is a bombastic tool for signal processing and connects nicely with the ADALM Pluto SDR. To create a spectrum analyzer in GNU Radio, follow these steps:
- Install GNU Radio on your system.
- Install the gr-iio and gr-plutosdr blocks for the ADALM Pluto SDR connection.
- Use GNU Radio Companion (GRC) to create a flowgraph crafted from the Pluto SDR source, an FFT block, and a Waterfall Sink for visualization.
Here's a basic GRC flowgraph concept:
- PlutoSDR Source: Set the frequency and gain.
- FFT Block: Use this to morph time-domain data into frequency-domain data.
- Waterfall Sink: Present the spectrum.
Lock-in amplifier
The lock-in amplifier technique measures the amplitude and phase of a signal by mixing it with a reference signal of the same frequency. This technique boosts sensitivity and signal-to-noise ratio but requires a reference signal that is phase-locked to the input signal.
In Python, creating a lock-in amplifier demands generating a reference signal, mixing it with the received signal, and then filtering the result. However, this is more intricate and usually requires additional hardware or specialized simulation tools for detailed implementation.
In the world of software-defined radio (SDR), the Pluto SDR can be transformed into a high-performance spectrum analyzer, thanks to its alliance with science, technology, and programming tools like Python and GNU Radio. This marvel performs brilliantly, scanning a frequency range of 100 MHz to 6 GHz, while the lock-in amplifier technique ensures fine-tuned sensitivity and signal-to-noise ratio. Aside from the basic hardware like the ADALM Pluto SDR, USB connection, RF bridge or coupler, and suitable antenna, the process involves programming with Python libraries andcreating a flowgraph in GNU Radio for a captivating spectrum visualization.
