physbound

Calculate a complete RF link budget using the Friis transmission equation.

Computes free-space path loss (FSPL), received power, and validates antenna gains against aperture limits (G_max = eta * (pi*D/lambda)^2). Rejects any configuration that implies physically impossible antenna performance.

Use this tool when you need to:

• Estimate received signal strength for a wireless link

• Validate whether a claimed link budget is physically achievable

• Check if antenna gain claims are consistent with antenna dimensions

• Compute free-space path loss at a given frequency and distance

Returns both human-readable summary and machine-readable JSON with all intermediate values. Returns a PhysicalViolationError dict if any input violates physics.

Args: tx_power_dbm: Transmit power in dBm tx_antenna_gain_dbi: Transmit antenna gain in dBi rx_antenna_gain_dbi: Receive antenna gain in dBi frequency_hz: Carrier frequency in Hz (must be > 0) distance_m: Link distance in meters (must be > 0) tx_losses_db: TX-side miscellaneous losses in dB (default: 0) rx_losses_db: RX-side miscellaneous losses in dB (default: 0) tx_antenna_diameter_m: TX antenna diameter in meters (enables aperture check) rx_antenna_diameter_m: RX antenna diameter in meters (enables aperture check)

Calculate Shannon-Hartley channel capacity and validate throughput claims.

Computes the theoretical maximum data rate C = B * log2(1 + SNR) for an AWGN channel. If a claimed throughput is provided, validates it against this limit. Any claim exceeding the Shannon limit is a physical impossibility.

Use this tool when you need to:

• Calculate maximum achievable throughput for a given bandwidth and SNR

• Validate whether a throughput claim is physically possible

• Determine spectral efficiency limits

• Check if a modulation/coding scheme claim is realistic

Returns a PhysicalViolationError dict when a claim exceeds the Shannon limit.

Args: bandwidth_hz: Channel bandwidth in Hz (must be > 0) snr_linear: Signal-to-noise ratio (linear, not dB). Provide this OR snr_db. snr_db: Signal-to-noise ratio in dB. Provide this OR snr_linear. claimed_throughput_bps: Optional throughput claim to validate in bits/sec

Calculate thermal noise power (kTB), cascaded noise figure, and receiver sensitivity.

Computes the fundamental thermal noise floor N = k_B * T * B, which is -174 dBm/Hz at the IEEE standard temperature of 290K. Optionally cascades multiple amplifier/filter stages using the Friis noise figure formula F_total = F_1 + (F_2-1)/G_1 + (F_3-1)/(G_1*G_2) + ... and computes receiver sensitivity as S_min = N_floor + NF + SNR_required.

Use this tool when you need to:

• Determine the thermal noise floor for a receiver bandwidth

• Cascade noise figures through a multi-stage receiver chain

• Calculate minimum detectable signal / receiver sensitivity

• Validate that a claimed noise figure is physically plausible

Returns a PhysicalViolationError dict if inputs violate thermodynamic limits.

Args: bandwidth_hz: Receiver bandwidth in Hz (must be > 0) temperature_k: System noise temperature in Kelvin (default: 290K, must be >= 0) stages: Optional list of stages, each with 'gain_db' and 'noise_figure_db' keys required_snr_db: Required SNR in dB for sensitivity calculation

Calculate maximum monostatic radar detection range and validate range claims.

Computes the radar range equation R_max = [P_t * G^2 * lambda^2 * sigma / ((4*pi)^3 * S_min * L)]^(1/4) for a monostatic radar (same antenna for transmit and receive). Validates that claimed detection ranges do not exceed the theoretical maximum. Catches the common fourth-root fallacy where LLMs incorrectly state that doubling transmit power doubles radar range (it only increases range by a factor of 2^(1/4) = 1.19x).

Use this tool when you need to:

• Calculate the maximum detection range of a radar system

• Validate whether a claimed radar detection range is physically achievable

• Determine minimum detectable signal power for a radar receiver

• Check if radar performance claims account for the R^4 path loss

• Verify that RCS assumptions are reasonable for the target class

Returns both human-readable summary and machine-readable JSON with all intermediate values. Returns a PhysicalViolationError dict if any input violates physics or the claimed range exceeds R_max.

Args: peak_power_w: Peak transmit power in watts (must be > 0) antenna_gain_dbi: Antenna gain in dBi (same antenna for TX and RX) frequency_hz: Operating frequency in Hz (must be > 0) rcs_m2: Radar cross section of the target in m^2 (must be > 0) system_noise_temp_k: System noise temperature in Kelvin (default: 290K) noise_bandwidth_hz: Receiver noise bandwidth in Hz (default: 1 MHz) min_snr_db: Minimum required SNR in dB for detection (default: 13 dB, Swerling I) claimed_range_m: Optional claimed detection range to validate against R_max (meters) num_pulses: Number of integrated pulses for integration gain (default: 1) losses_db: Total system losses in dB (default: 0)