tda5670-5x ETC-unknow, tda5670-5x Datasheet - Page 14

• Manufacturer Part Number: tda5670-5x
• Description: Video Modulator Fm/am-audio With Pll-output
• Manufacturer: ETC-unknow

Test Circuit 4
Description of the Measurement Configuration to Measure the Audio and/or Noise
in Video during FM- and AM-Modulation of the Audio Carrier
Calibration:
1) Measurement of audio interference product ratio in video while the audio carrier FM modulated:
2) Measurement of signal-to-noise ratio in video without FM-modulation of audio carrier: AF-signals
3) The noise limit of the measurement device is approx. 85 dB.
Semiconductor Group
AF-signal is connected to FM-audio input; video signal is present at video input; Modulation
measurement device set at AM; filter: 300 Hz...20 kHz; detector: (P+P)/2; the automatic RF-level
position of the measurement device is switched off; wave analyzer at video signal level 1 kHz or
2 kHz or 3 kHz adjusted and resultant level is set to
from a
are switched off; video signal is switched on; modulation measurement device set at AM; filter:
300 Hz...3 kHz; detector: RMS x
out in dB to reference level of calibration is
A/V
= a
AF-signals are switched off, video signal is present at video input, modulation
measurement device set at AM is adjusted to video carrier; filter: 300 Hz...20 kHz;
detector: (P+P)/2; Wave analyzer at video signal level (16 kHz) adjusted and
resultant level as reference
A
-a
V
(dB).
2
; Wave analyzer at video signal level (16 kHz) detuned; read
a
v
defined.
a
N/V
14
.
a
A
.
The audio noise ratio in video results
TDA 5670-5X