Worked Example: 2.4 GHz RX Chain
Scenario: Design a 2.4 GHz ISM band receive chain that meets:
- Total gain ≥ 60 dB
- Cascaded NF ≤ 6 dB
This walkthrough goes from a blank canvas to a working design with analysis.
Step 1 — Build the chain
Type in the chat panel:
Add a Signal Source, Low Noise Amplifier, Bandpass Filter, Mixer, IF filter, Variable Gain Amplifier, and ADC in that order
The AI adds six blocks and connects them. The canvas should show:
[Signal Source or DAC] → [Low Noise Amplifier] → [Bandpass Filter] → [Mixer] → [IF filter] → [Variable Gain Amplifier] → [ADC]
Step 2 — Add the LO block
The AI sometimes automatically adds the LO block, if not. Type in the chat:
Add a Local Oscillator block and connect it to the mixer LO port
The LO appears as a support block — it won't be part of the cascade but enables the mixer's frequency conversion.
Step 3 — Set the System Spec
Ask the AI or open the System Spec panel and enter:
| Field | Value |
|---|---|
| RF center | 2440 MHz |
| RF bandwidth | 80 MHz |
| IF center | 140 MHz |
| IF bandwidth | 20 MHz |
| LO center | 2300 MHz |
| Operating mode | RX |
Step 4 — Enter Low Noise Amplifier parameters
Click the Low Noise Amplifier column in the Parameters workbench (or click the Low Noise Amplifier block on canvas). OR ask the Ai to Enter:
| Parameter | Value |
|---|---|
| Gain | 18 dB |
| Noise figure | 1.5 dB |
| IIP3 | −5 dBm |
| P1dB (input) | −15 dBm |
| Freq min | 2300 MHz |
| Freq max | 2500 MHz |
After entering gain and NF, the Analysis panel will show a partial cascaded NF. It won't be complete until all blocks have NF values. Also the OIP3 and OP1dB will be automatically computed based on the values
Step 5 — Ask the AI to enter or enter Bandpass Filter parameters manually
| Parameter | Value |
|---|---|
| Insertion loss (gain) | −1.5 dB |
| Freq min | 2300 MHz |
| Freq max | 2500 MHz |
A filter's "gain" is negative — enter −1.5 for 1.5 dB insertion loss.
Step 6 — Ask the AI to enter Mixer parameters or enter them manually
| Parameter | Value |
|---|---|
| Gain (conversion loss) | −7 dB |
| Noise figure | 7 dB |
| IIP3 | 15 dBm |
A mixer with conversion loss has negative gain. The noise figure of a passive mixer equals its conversion loss (7 dB here).
Step 7 — Ask the Ai to Enter IF filter and VGA or enter them manually:
IF filter:
| Parameter | Value |
|---|---|
| Gain | −2 dB |
Variable Gain Amplifier:
| Parameter | Value |
|---|---|
| Gain | 30 dB |
| Noise figure | 8 dB |
| IIP3 | 10 dBm |
Step 8 — Read the analysis results
With all parameters filled, check the Analysis panel:
System Totals (expected values):
| Metric | Expected |
|---|---|
| Gain | 18 − 1.5 − 7 − 2 + 30 = 37.5 dB |
| NF | dominated by Low Noise Amplifier → ~~4 dB |
Step 9 — Save a snapshot
Save snapshot as v1_baseline
Step 10 — Try adding a pre-LNA BPF
Add a second Bandpass Filter before the Low Noise Amplifier to test impact:
Insert a Bandpass Filter before the Low Noise Amplifier
Set the same parameters (−1.5 dB insertion loss). Observe that cascaded NF increases by ~1.5 dB.
Step 11 — Compare with snapshot
Open the comparison view and select v1_baseline. You'll see:
- Structural diff: +1 block (pre-Low Noise Amplifier Bandpass Filter)
- Analysis delta: NF worse by ~1.5 dB