Power output level: Greater or equal to +13 dBm (unmodulated carrier)
Modulation capability: 0% to 99% AM at 1000 Hz at carrier outputs up to
+7 dBm, both internal and external modulation capability
Linearity: Harmonics of the fundamental carrier frequency shall be at least 40 dB below carrier level (–40 dBc) at the maximum carrier power level used in the test set-up. With this carrier level, the AM distortion of the modulated envelope shall be less than 5% at an AM level of 80%.
Non-harmonic spurious: Less than –40 dBc
D.16RF wattmeter
This is for measurement of the directional coupler output. Any RF voltmeter with an input impedance of
50 Ω that can be calibrated in terms of rms (volts may be used as a substitute). Examples are spectrum analyzers, EMI receivers, and RF millivoltmeter instruments.
Frequency range: 0.6988 GHz to 63.0 GHz
Impedance: 50 Ω
Amplitude range of input: +20 dBm to +40 dBm (2.236 V rms to 22.36 V rms across 50 Ohms)
D.17T-Coil integrator
For the measurement of ABM1, the intended WD audio frequency magnetic signal, the true magnetic field amplitude of the T-Coil signal is required. The reading must be compensated for the combined effect of the probe and the integrator. A full-band or half-band integrator may be used, so long as the proper compensation is applied to the resulting readings. Either integrator, full-band or half-band, may be used so long as the resulting reading is properly compensated to give the true magnetic field amplitude.
For a broadband measurement of the noise, ABM2, a half-band integration of the probe coil voltage is required.
D.17.1Full-band integration
For the measurement of audio frequency magnetic signal, a full-band integration of the probe coil voltage output, shown in Figure D.14, is specified, in order to enable measurement of the magnetic field magnitude vs. frequency. This integration, which consists of a downwards-sloping 6 dB/octave equalization, must be maintained accurately over at least the 300 Hz to 3 kHz frequency range of the frequency response masks of 7.3.2. This integration may be applied directly to the buffered probe coil signal, or mathematically in post-processing according to the inverse of the probe coil response defined in Figure C.4. The full-band integration frequency response is shown in Figure D.14, with the resultant integrated probe response to
a constant field magnitude shown in Figure D.15. The resultant sensitivity shall not deviate from the uniform characteristic shown in Figure D.15 by more than 0.5 dB over the frequency range of
300 Hz to 3 kHz.
D.17.2Half-band integration (T-Coil response)
For the measurement of ABM2, the undesired WD audio frequency magnetic signal, a half-band integration of the probe coil voltage output, shown in Figure D.14, is specified, in order to simulate the magnetic frequency response of a typical hearing aid T-Coil. This integrates only the frequencies above
1 kHz, resulting in a first-order low-pass filter characteristic with a corner frequency of 1 kHz being applied to the probe coil output. This equalization should be maintained over at least a frequency range of 100 Hz to 10 kHz, since the measured noise signal is not limited to the narrower ABM1 bandwidth. This filtering may be applied directly to the buffered probe coil signal, or mathematically in post-processing. The primary calibration of the half-band integrated probe coil response is at 1 kHz. The applied half-band integration frequency response is shown in Figure D.14, and the resultant modified probe response to a constant field magnitude shown in Figure D.15. The resultant sensitivity shall not deviate from the characteristic shown in Figure D.14 by more than 0.5 dB over the frequency range of 300 Hz to 3 kHz and 1 dB over the extended range of 100 Hz to 10 kHz.
Figure D.24—Full- and half-band integrator responses
Table D.11—Full- and half-band integrator responses at 1/3 octaves in decibels
relative to 1 kHz